Welcome to the Q&A Forum

We're using Optimizely and we love it.  Their tool is incredibly easy to use, and very powerful.  It's powered by jQuery, but has a nice editor (which you can try out for free on any page on your site) where you can edit page elements simply by clicking and dragging, resizing, swapping, or deleting them.  For a lot of our tests, we handwrite JavaScript and jQuery to effect multiple elements on multiple pages, which was impossible for us to implement within Google Website Optimizer. They also have all the reporting you'd expect and support multiple goals which is a must for us.  It's a very powerful full-featured tool.  We're very happy with it and have no regrets.