I considered the SLX's for my family room, because they are on-wall. A friend of mine went ahead and bought them, and I decided to wait, he found them at $200.00 ea. at local Klipsch dealer. He hates them, and is going to list them on Ebay to get something else. When I first heard them I found them extremely annoying, that is why I decided to wait. At $140.00 they might seem like a good buy, but be careful, as you might not like them and it will cost you more to upgrade.
In my case, I finally decided to go with PSB Image Series, due to many reasons (price, quality, reviews, SQ, better extension than on-walls, etc.), and I am extremely happy with my decision.
But, I can understand the reasons why people like on-walls (convenience, looks, WAF, space, etc.). Here is a list of on-walls with reasonable prices that I considered and audition (listed on order of preference):
Paradigm Cinema 220 and 330: I really liked the 330's they sound really nice for music and HT, and probably offer the closest sound to towers or bookshelves in their price range; obviously you need a sub to complement them. The 220's even though don''t have the extension of the 330's, they sound very good, and 20 times better than the SLX.
Monitor Audio R180 and R225: Very pretty, different finishes available that will please the wife, nice laid back sound with detailed mids; maybe better than Paradigm for music, but you get them mainly for HT, so I liked Paradigm's being more dynamic. MA's have a more refined sound, more neutral. Also, a sub is needed.
Energy: Don't remember their series name, but where too forward for my taste. Still they sounded nice and might provide that extra dynamics that some people desire for movies. The dealer had ruined the experience for me as he made me listen to Vienna Acoustics on-walls prior to the Energy on-wall.
Klipsch RVX-42: Much better sounding than the SLX. If you like Klipsch's signature sound (extremely detailed with loud highs) the RVX delivers as an on-wall. The SLX cannot even get close to the RVX. Prices I have seen in the States are too high for this, so shop around; maybe the same people that have those SLX at such an inexpensive price can sell the RVX at a reasonable price. RVX are not worth the $350 to $400 price being asked in the States. Here in Puerto Rico a dealer has them in stock at $279.00 ea.
Athena WS: Didn't care for them.
I also auditioned offerings by Vienna Acoustics (awesome on-wall speaker), Boston P-Series, Martin Logan, and Def Tech...All at almost twice the price of the ones mentioned previously, but all much better. Vienna and Martin come the closest to floorstanders.
Be advised that for on-wall a sub is obligatory, as it is what gives them that full range sound.