ive had a thunder tiger phoenix XB pro (brushless version) and it was a great buggy for the money.
It is basically a team associated B3 with updated electronics. The B3 is an older racing buggy, but it still handles well and is pretty tough.
The phoenix was $200 on tower hobbies last time I looked. For that, you get a RTR brushless 2wd buggy with a ball diff, nice 2.4ghz radio and CVD driveshafts.
I had a couple of small "out of the box" issues with mine. The ESC was not attached to the chassis (double sided tape sucked) and the slipper clutch was way loose (just needed to be tightened) and how the wires were run was sloppy (a few zip ties fixed that)
The brushless system provides plenty of punch. for some reason tho, thunder tiger geared it lower than is needed. A $5 pinion gear that was a few teeth larger gave much better top speed and it still ran fine.
Only other issue was that the rear tires did wear out fairly fast. They are a softer "race" rubber. But there are plenty of bolt on wheel/tire combos available.
The diff/driveshafts/chassis ect are all tough. I ran that buggy hard and I think other than the front shock tower I didn't break much.
factor in the cost of a $30 2s 5000mah lipo battery and a $50 lipo battery charger and you still stay under $300 for the whole package.
The traxxas bandit xl-5 is also in your price range. It wont be as fast due to its brushed system, but it is still fairly quick and being a traxxas there are tons of upgrade and hop up parts available. I think the RTR brushed verisions (with a battery/basic charger) run $225-250.