RE: Going from electric to gas
razor really hit the nail on the head. you should always get an instructor to help you out. i learned to fly years ago, got out of it, and thought i could still fly the same!(good ole' hard headed me) needless to say the results weren't pretty. i only lost a prop in my ordeal, then i found a club and got some good training. .40 are generally easy to control, and altitude is your best friend when learning how to fly. i learned on an alpha, both times i learned, which is very similar to the eagle 2. (as far as the ease of flight) they can be a little fast, but just don't make it that way. as with any plane you can control the speed. 1/2 throttle is a good cruising speed which will allow for tight turns without losing altitude, but also slow enough to handle for a beginner.
cherry made a good point about the club and ama. ama is insurance for your plane if you crash into someones car, property, or even a person. i wouldn't fly without it. as far as an instructor, i have been flying for quite some time now, and every time i get a new plane i always have the guy that re-taught me to fly look at the plane and test fly it to double check it's safety. if you join a club(most of the time you have to join to use their field) it is easy to find someone that will teach you how to fly, tune the engine, and trim out a plane. after a while you can do all the above on your own. i still have my instructor help me, and i am a very proficient pilot.
over all, everyone has given good advice, take it to heart. i want to welcome you to the world of flying r/c, wish you the best of luck, and i'd like to congratulate you when you start solo-ing. so keep posts on your progress!
-james