The Truth series is an active monitor (self-powered).
M&K makes awesome active speakers/monitors.
Genelec makes great ones too, as do a number of other companies.
Those Behringers are "low-budget" active monitors but are great for the money and would work just fine in a home theater application. I have seen a number of people use them in DJ booths at big clubs and such as near-field monitors. That seems to be their big intent. The Truth's are basically Genelec clones and are a good entry level studio monitor. But the Genelecs are far more expensive.
I'm partial to the "Studio monitor" sound and companies that stick to that: M&K and Genelec, more specifically. I have found that my M&K S-150s (the passive version, they also make an active version - even more expensive though) sound better then speakers many times their price.
When shopping active, the internal amp makes a big difference in sound too. That Behringer probably doesn't have a very impressive amp and probably just has one handling both the highs and lows (which a higher end one will have seperate amps).
-Chad
