I have a Steelcase Leap and I love it. Bought it from SmartFurniture.com and I highly recommend them, too. They price match, and if you don't like the chair, they pay return shipping if you change your mind within 30 days (and haven't done bad things to the chair, of course). I love my chair, but the first one wound up defective (horrible squeaks and scary clunks) after a few months. Smart Furniture arranged for Steelcase to take back the chair, and ordered me a brand new one, which has been fine.
Next, we ordered a Herman Miller Aeron for hubby. He'd had one at work and loved it, but found this one horribly uncomfortable. We took SmartFurniture up on their return policy, and they took the chair back with zero hassles. Only caveat we found is if you can't bring the chair to UPS (and we couldn't), you'll have to pay the small fee for the home pick-up.
If you can, it's always best to try out chairs in person. I was able to find a (relatively) close dealer to try out the various Steelcase options, but the closest Herman Miller showroom was a three hour drive. The key thing to remember is that everyone is different, so the perfect chair isn't the same from person to person.