LiveAgent

LiveAgent offers 3 pricing plans:

Ticket

$9 per agent/mo

Main features include:

Custom domain parking
E-mail support - Ticketing
Contact forms
Forum & Knowledge base
iPhone/Android app

Ticket + Chat

$29 per agent/mo

Main features include:

All Ticket features
Live Chat
Real-time visitors monitoring
Chat invitations
Feedback management

All-inclusive

$39 per agent/mo

Main features include:

All Ticket + Chat features
Facebook & Twitter
Call center support
Video call
Time tracking
Gamification

Features like Live Chat, Real-time visitors monitoring, Chat invitations or Feedback management are only available starting with the Ticket+Chat. And Facebook & Twitter, Call Center support, Video call, Time tracking, Gamification are only available for the All-inclusive plan.

The 14-day free trial starts with the All-inclusive plan, and there's no credit card required during your trial period.

Zendesk Support

Zendesk Support offers 4 princing plans:

Essential:

$5/mo per agent when billed annually
or
$9/mo when billed month-to-month

Main features include:

Unlimited email addresses
Twitter and Facebook channels
Basic knowledge base
Agent Macros

Team:

$19/mo per agent when billed annually
or
$25/mo when billed month-to-month

Main features include:

All Essential features
Branded Help Center
Customer portal
Public Apps Marketplace

Proffessional:

$49/mo per agent when billed annually
or
$59/mo when billed month-to-month

All Team features
Multilingual content
Insights analytics
Custom private apps

Enterprise:

$99/mo per agent when billed annually
or
$125/mo when billed month-to-month

All Professional features
Custom agent roles
Multibrand support
Multiple schedules
Hourly Insights analytics

The 30-day free trial starts with the Professional plan. No credit card is required and there are no cancellation fees. If no payment method is added at the end of the trial period, the account is deleted 90 days after the trial expiration date.

Zendesk is a bit more pricey but for annual billing you'll get a 15% discount.

LiveAgent

LiveAgent's design is not as up to date, the dashboard is a bit cluttered but intuitive. You may customize it up to one point by adding custom branding.

The interface seems to be geared towards users that have some experience with this kind of software, so if you're just starting out you might need to go through some video tutorials first.

Zendesk Support

Since August 2016 a new version of the agent/admin interface of Zendesk is available, with a more clean and modern design. You can choose from a selection of templates that will match your brand or simply start creating your design from scratch.

LiveAgent

LiveAgent has more than 170 support features and some of the most important include: Automation, SLA, Ticketing, POP3 accounts, Email piping, Departments, Priorities, Statuses, Tags, GIFs in tickets, Rules, Ticket Routing, Canned/Predefined messages, WYSIWYG editor, canned ResponsesMacros, Email templates, Performance Reports, Voice integration and call recording.

Zendesk Support

The Help Center is designed to give you a complete self-service support option (knowledge base). Users can use the information you are providing or turn to a community forum for answers.  Your Agents can also use the Help Center to help solve tickets. You can deliver all the content in multiple languages.

Top features include: Unlimited email addresses, Twitter and Facebook channels, Knowledge base, Branded Help Center, Public Apps Marketplace, Multilingual content, Business hours & SLAs, Insights analytics, Multibrand support, Auditing & admin controls.

LiveAgent

The Dashboard gives you overall information about what's happening into your account, in the Chat section you can see your online visitors running in pending chats, in the Tickets section you can view all the communication between you and your customers. Next, the Reports tab gives you insights on overall performance, agent performance, department, or channel reports. Customer portal allows you to create, manage and customize your online knowledge base.

Zendesk Support

Zendesk will give you the option to transform your interface to match your brand. With familiar customization tools, you can easily tailor the look and feel.

There are five menu items on the left side of the screen:

First, a Home button gives you access to your dashboard, where you'll find a snapshot of your current configuration. On the Views section you'll find your unsolved tickets.

Next is the Reporting section, where you will get detailed snapshots of ticketing, agents, customers, self-service, and more. Last button on the bottom left corner will take you to your settings, where you'll find all the fine-grained controls for your account.

The last button in the bottom left of the screen is a link to the Admin home page, here you'll find the tools you need to configure Zendesk.

Two more menu items can be found on the top right corner:

First (next to the search box) is a menu item that lets you select between the Support section and the Help Center. Next, if you click on your avatar you can access all your Profile Settings.

LiveAgent

LiveAgent is the most affordable help desk software we have reviewed. The $12/agent fee makes LiveAgent great for small businesses and independent freelancers. The interface is simple and intuitive, making it an application that is easy to learn, use, and implement when you’re just starting out.

Zendesk Support

Without a doubt Zendesk is the most popular help desk sofware out there, this doesn’t mean that there is no competition. Using Zendesk if you have a small team would work fine, even tough . Zendesk will best suit you if you are planning to expand or you already own a large company that will require advanced features like advanced analytics and reporting, segmentation or retargeting.

LiveAgent

LiveAgent has a strong reporting section. Even if you're running a one-man business or a medium size organization, every report tool is available, from department reports, usage statistics, performance reports, agent rankings, customer satisfaction ratings and detailed insights of every communication channel: Email, Live Chat, Call Center, Contact Forms, or Social Media messages.

Zendesk Support

Zendesk Reports are available for all plans and provide metrics such as daily ticket activity, service level agreement compliance, average resolution time, customer satisfaction, agent performance, ticket resolution time, and efficiency.

Insights provides advanced reporting and metrics but is available only for the Professional and Enterprise plans.

LiveAgent

LiveAgent has a great set of features making it one of the most competitive help desk software out there, therefore a native iOS and Android app is available, so you can provide customer service while on the go. The app will allow you to transfer and respond to tickets, chat with your customers, or get push notifications of new tickets or chats.

Most importantly, LiveAgent has also an integrated live chat feature that is included starting with the Ticket + Chat plan. If you're looking for a live chat option too, then LiveAgent will be an affordable option.

A big plus for LiveAgent are the 39 translations available, so your agents can use LiveAgent in a language they prefer.

Zendesk Support

Zendesk offers a built-in chat option and phone support software (both paid separately), a mobile app (both for iOS and Android), integrated apps so that you can offer fully scalable customer support. The Help Center gives you a lot of flexibility.

If you're planning on expanding your support team, Zendesk will give you more flexibility but will be a bit costly.

LiveAgent

There are only 41 integrations at the moment but most of the popular online services are available: MailChimp, AWeber, Braintree, Shopify, Facebook, or Twitter.

If you're code savvy and you're really tied to a particular web service there is an API available for creating integrations.

Zendesk Support

Zendesk offers more than 350 integrations available, called apps.  The apps are found in the Apps Marketplace with  some of the most being: SalesForce, ZenCart, Magento, JIRA, TeamViewer, Drupal, Joomla, Wordpress, PlanBox, MailChimp and 8X8. If you wish to create your own custom app, you can take advantage of Zendesk's API.

LiveAgent

The support section is not as friendly and well organized as you would expect. There are 25 video tutorials available, a getting started section, a technical section (including FAQs) and a support forum.

If you need some fast answers, a live chat option is available on the homepage or you may reach their support by email, phone and social media.

Zendesk Support

Zendesk has a dedicated support section where you can access the knwoledge base, Getting Started tutorials and the community forum.
If you can't find here the answers you need, or you just need to get in touch with them about pricing or billing, then you have all the options available: contact form, phone support (with separate phone numbers for different countries and time zones) and social media (if you're looking for a quick answer).