The VMar Discovery ARF is a nice trainer plane. There is even a pretty thorough review of it here on RCU:

http://www.rcuniverse.com/magazine/a...?article_id=31

The JR Sport SX600 radio system is only $20 more than the Futaba 4YF that you're considering, but it's a 6-channel computer radio with 10 model memory. I'd strongly consider spending the extra $20.

The Super Tiger G-45 ABC is an outstanding engine, but so is the Super Tigre G-40 ringed. You could buy the less expensive G-40 engine and still have loads of power for your Discovery trainer ARF. This would free up $15 extra for the radio upgrade.

The Discovery ARF with G-40 and SX600 radio system would be a great training platform and a great value.