Ok, if you spend enough time reading forums, product reviews, searching manufacturer web sites, visiting your local retailers, etc.. You will surely find a massive array of in-wall, in-ceiling and even on-wall speakers with price ranges that are staggeringly different especially when you compare them on 'paper'.
I have personal experience listening to HTD's, PSB's, JBL's and KEF's. I've heard a few more of the cheap ones at Best Buy etc., but don't recall the brands at the moment. All-in-all they sound much closer than the price differences would suggest. I understand that they are each influenced by a multitude of factors such as ambient noises, amplification, cables/wires, room accoustics and so on and so on and so on...
Bass response is usually very anemic while the highs and mids can be very impressive and accurate. In certain examples I have even been impressed by the imaging created by of a pair of in-walls.
Soooo..., having considered the aforementioned, how does one decide between one pair or the next? One thing I'm sure of is that there are diminishing returns as you climb the price ladder. My two cents anyway.
Best regards