They're real cool. I got a pair to basically act as poor man's mains, but I've mixed a few things on them, and have found they translated well. EQ Magazine, not one to give Behringer props for anything, actually gave them a pretty good review, and so did a couple of other mags. They also got slammed by ProRec.com. For me, they've done the job I needed them to do quite nicely.
Keep in mind that, more than any other piece of music production-related gear, monitors are HIGHLY subjective. One man's gold is another's trash. That's why for all those that HATE NS-10s and HR824s, there are an equal amount that think they're the greatest monitors ever made. And more than any other gear, maybe with the exception of mics, monitors are HIGHLY dependant on the room they're in. So that's why you'll get some people saying they sound one way and others saying they sound another way.
Spend time at the store, and LOTS of time at home with them and possibly make good use of the return policy. No matter what you get, be they BX8s or ADAM S2.5s, you still HAVE to learn those monitors, particularly how they act in your room. So if all you can get is something under $500, then that's all you can get. Hundreds of millions of records have been sold that've been mixed on NS-10s, and they're neither good (IHMO) nor expensive monitors, yet people swear by them. Get what you can get and upgrade when you can.
Peace
