Actually, both Airtronics and JR use positive shift, to set the record straight.
Both the HiTec and FMA receivers are good units (have used both extensively with nothing bad to report).
If you purchase a HiTec model 555 (if you only need 4 or 5 channels, you have a unit capable of taking care of your needs for a large plane as well as one which will fit a small plane. You might check Servo City (www.servocity.com) for their prices on the HiTec. Good flying.