Harnesses come in many different styles. I've tried several styles and own more than a dozen harnesses. The padded harnesses are nice but I prefer the slim webbing harnesses when canyoneering because they are low profile and don't rub and catch on everything. They also have the advantage of being very inexpensive.
The one feature that is an absolute must for me is the automatically locking straps that you don't have to double-back. I have several harnesses that require the straps to be double-backed, and I hate them.