There are LOTS of trainers on the market... most are decent, but a couple stand out better than the rest.

Sig LT-40 is about the best. (especially if comparing ARF models)
THe RCM Trainer, by Global Hobbies is another very good one, and there was (may still be) a deal where the trainer plus engine (ARF) was $139... hard to beat price. (Needs the engine compartment painted with 2 hour epoxy... fuelproofing and improves engine bearer joints, the only bad point of the model.)

I would recommend not getting the US AirCore trainer... its on the heavy side. (but it is durrable...) The Duraplanes are also heavy. Heavy trainers make it harder to learn.