I own the SX-HTB and I think they are great for the money. I bought it from a local guy who upgraded to $800 Dahlquist speakers after owning the Fluance for 3 month. As a matter of fact, when I went to the guy's place for audition, and after comparing the two sets of speakers side by side, we noticed that the Fluance actually has more bass than the Dahlquist, the sound was clearer on with the Fluance, not to mention the craftsmanship on Fluance was better (agree with the others on the logos though). He was actually a little upset about having to let go the Fluance after the comparison.
Fluance has pretty clear highs, and some people may consider it "harsh". It is pretty good with movies, you can definitly "feel" the sound effect, I can tell the wall shaking a bit when watching Master and the Commander with all the canon firing. But if you want bass that shakes the whole house, yeah go with additional sub.
I use the Fluance with a Marentz 5300 receiver and a NAD cd player, using my HTPC as the DVD player. Pretty happy with the sound from a $250 speaker (actually 220 and no shipping from the local guy, 3 month used

) . I've heard plenty of speakers and to get significantly better sound, I would have to spend more than 1k for a 5.1 package.
Definitly a great set of speakers for people who just getting into audiophile world and not wanting to invest 2~3K right away. People who say those are crappy speakers either never listened to them or don't have decent components hooked up to them.