First Off - I believe these retail @ $500/pair (review says $400/pair). Things could have changed since my last price sheet (fall 2007), but I'm fiarly sure that's what these retail for.
I had the chance to demo the TK-5C in my home (not had the chance to use them on a project yet - mostly because our projects start above these $ wise) and they sound very good. Excellent, really when you factor in price/value. I had them hooked up in an office to a Parasound ZAMP with a Sonos ZP/80 for the source and they rocked. I A/B'd them with a pair of RBH 41-SE Signature Series book shelves I had sitting around in the garage. It was obvious that the 41-SE was in a different class but, @ their price point, the TK-5C had a great sound on its own and would make a fine starting point for a [better than entry level] HT or music system. For rear channels or distributed audio the TK-615 in ceiling speaker is really nice for the $. I use these in my own kitchen and @ $350 per pair I think they're a steal (but I would still like to see a 1" tweeter instead of the 3/4"). Point being: you can put together a nice HT using voice matched TK for all 5/7 channels.
At it's price point I don't think anyone can rightfully have a lot of complaining to do about the RBH TK line of speakers.