I tried to replace the Leap with a Mirra from Herman Miller. But I just couldn't adjust it to what was comfortable for me. And I didn't like the back. I'm not a fan of the webbing.
I gave it to my wife, and she loves it. But granted I upgraded her from a 80 dollar Office Depot chair :)
You should see if there are office supply stores near you that will let you demo the chairs. Not just for a few minutes but for at least a day.
A friend of mine just bought 15 Leap's in AZ. He was able to get a Leap, Mirra, and a couple of others to test out for a couple of days before making his decision. Might be something to look for in your area.
In general I've been pretty happy with build quality. However, one of my arm rests is jammed and won't raise atm, and I'm too poor to afford a replacement part.
My office is in a friend's living room. His brother has an Aeron he lets us borrow, so the rule is whoever starts work first gets the Aeron for the day and everyone else has to sit on the folding chairs. =) Gets us going in the morning!
Luckily a neighbor just moved, leaving us several standard office max chairs. As chairs go, they're not much, but they beat the plastic ikea folders.
For years I had an old office chair. Got it used from a bank. I was happy with that. But eventually it was worn out. Tried a lot of office chairs. Never found anything like it.
One day it struck me. This armchair of mine, which I used to sit and read in for hours, why not put wheels under it. I did. Four sturdy rotating 4" wheels. Made the chair a little higher which is perfect.
As a freelancer I've worked in the offices of a good number of large enterprises and so trialled several office chairs. I've found that, once it's set up right for you, the Aeron is hard to beat for comfort, particularly over protracted periods.
Comfortable and a great price too!