I have tried a number of pads and don't think I've ever quite gotten it right.
My QH is ridiculously wide and "mutton withered," so saddle fit has always been a problem. I have "compensated" by using thin pads and it's only made matters worse. In my ignorance, I pretty much ruined my horse and he's now retired at age 22 (been retired for 4 years). Pads I tried on him: "fleece" pads, including "cool back" fleece, thick (cheap) "rug" style pads with fleece lining, thin wool "show" blankets with a felt liner.
With my Arab, I tried a couple of different pads: a fleece pad with a "tacky too" type lining, a regular fleece pad, and a Charmayne James Pro Choice pad. The tacky too pad worked best, and he HATED the Pro Choice pad. I bought it used, and actually thought there was something wrong with it at first due to the crinkly noise. I will agree with the poster that said they don't like them AT ALL.
I now have a new horse and am currently pad shopping. Here's my thread, also lots of valuable input in there: Saddle pad recommendation - Western
My trainer likes Pro Choice or thick wool felt pads. I think I'm going to go with either an ESP pad or a wool felt pad. I'm going to try and find a contoured pad in my budget.. it just seems like they would fit the horse a lot better than a straight pad.
I'm actually going to up my budget a lot for a pad, though... I think focus is so much on saddle quality that we tend to overlook the importance of a pad. I'm expecting to spend at least $100 - $150 for a pad... hoping to keep it under $200, though.
My biggest problem now is that most of the pads I'm finding are HUGE. It seems most are made to fit the oversized show saddles. Since I plan on getting a "regular" sized saddle, I don't really want 6+ inches of pad sticking out.