I currently have these speakers as my surround speakers. I have the crossover set at 100 hertz which is generally the recommended crossover point for these speakers. I have a Klipsch SUB-12 to fill in below 100 hertz. These are very solid speakers. The build quality is very good, they may look like plastic computer speakers in the pictures you see of them on line, but they are NOT light weight or flimsy in any way. The base swivel mount is very flexible so you can mount the speakers on the walls or ceiling if you want to. The only small complaint about the wall mounting option is that the speaker does end up sticking quite a ways out into the room, though this may be a non issue depending on your specific mounting locations in your room.
The biggest selling point of this speaker in my opinion is the horn tweeter. This horn tweeter really makes this speaker ahead of other speakers similarly priced in this size/utility range. The woofer does a great job of midbass and above, but simply was not made to go much deeper than 100 hertz, so matching this speaker with a subwoofer is a must. It's sensitivity also puts it above most other comparable speakers in this price range. I bought these speakers refurbished from Klipsch and paid about $160 for the pair - Money well spent!! These speakers would work great as main speakers, surround speakers, rear speakers just as long as you are using a good subwoofer as well.

My system specs for reference:
Receiver - Denon 2308Cl
Main speakers - Klipsch KLF-30's
Surround speakers - Klipsch RSX-5's
Subwoofer - Klipsch SUB-12