My pick would be the JR 9303 if you want to spend the less the JR 8103 is still a great radio, and it's what I use, but it has a lower price than the 9303. Less than the 8103 from JR isn't worth the time or money for a heli since you'll want more in short order.

I think from Airtronics it'd have to be the RD8000.