I would look into a thundertiger minitian or a dragonus II (which is a real deal at $150 with motor & controller). I have a minitian I fly around the yard and if the budjet allows, I'll soon have a dragonus. Both are super stable. I use DN power batteries as I bought a package deal that comes with 2 batteries a decent charger for $150. Another good one is a package deal from heliproz. For $500.00, you get a trex 450 with batteries and a spektum radio. Everything needed to get in the air.

As far as the walkeras, in my opinion, I would steer clear of them (quality issues) and don't even think about blade CP's unles you like radio glitches and replacing the tail motor every 10 flights. I have one that I am totally frustrated with and it sits on the shelf now.