Pros: Convertri makes building landing pages and funnels fun and easy. It uses drag and drop, which makes everything so much faster to design. Support and development is good; their FB user group gets daily posts and replies by the founders. I would absolutely go with Convertri over Clickfunnels or Kartra, and not just for the price, but for ease of use and quality of support. The learning curve is minimal for non-techies. No page builder is perfect, but Convertri is the best I've found. 

Click funnel receives only email support if you are a regular email holder while the enterprise account holder gets priority phone support. LeadPages customers receive better support if compared. While regular members receive only email support, Pro members enjoy live chat and email support, and Enterprise members gets all three: Live chat, email and phone support.
Like LeadPages, but focused more on templates and modular drag-and-drop building than the additional features. You can implement a welcome gate, you can use two-step opt-ins or three-step signups, and you have an image editor build into the system. On top of all of that, it has a bunch of bundled in analytics, giving you more data than most of the other programs on this list. They also have a 60-day money back guarantee, which is twice as long as most of the rest. They also have an unlimited annual license for $200.
Hey Martin, Yes Instapage is really good alternative to Leadpages. A/B test of landing pages are required, when a marketer need to test and optimize the performance of their existing lading page. Using A/B split test; they can change and optimize different elements of landing pages and see how the changes can impact their conversion to get high return.