They are basically the same... the SR300 is Spektrum's "budget" receiver... for the $10 less, you will need to use the "binding" plug (instead of an onboard button) and it does not work with their "telemetry" package... not a big deal though..
This appears to be the same receiver Losi sells with their RTR/BND kits.. MRX-3000 (LOSI B0806)... for $5 less than the SR300
All 3 receivers are DSM 1.0 and will work with all Spektrum transmitters and modules (for ground use).
Jerome
