Buy a Sig Kadet Senior! (not the Lt-40)
It is the best looking trainer, with curves, real windows, (not paint), and is more fun to fly than any other!
It  has a 80 inch wingspan, so you will have less orientation problems, and be able to fly further away.
When you are done training, it is fully aerobatic on a 60 or larger, and you will never want to sell it or give it
away!
RTF's are easier to set up, but will not give you any skills in radio setup, engine mounting, construction, etc.
Also, by getting an ARF or kit, you will be able to buy a better radio and engine that will transfer to your second
model easier.
You can even put a 91 fourstroke up front and practice zoom climbs and hover! (it will hover with a 70 if you use the
right prop)

Have fun!

Graeme