Basically Leap & Please are the top end followed by Gesture & Think which are more aligned with the Vertigear Triigger series
I was under the impression that the Gesture would be above the Leap v2 in the range.
I should probably just pick up a Leap, but the longer back, deeper padding and those fully moveable arms make the gesture very tempting.
I use a Herman Miller Aeron at work, which I find is a very very good chair, but I wouldn't call it overly comfortable/relaxing. Other than the front edge which can dig in a bit depending on how you're sitting, it just feels supportive and not something you can relax in and get some work done. (if that makes sense to anyone)
So, I'm looking towards Steelcase's offerings which tend to be highly recommended and people say are more comfortable than the HM Aeron (providing you adjust the chair to fit you).