I'm about to retire my trainer, so some advice is based upon all that it went thru:

If you buy a trainer, look for the Evolution engine. It is a very easy engine for your first one. You don't need to spend time tinkering around with engines- you need to be flying with an instructor. The Evo is always easy to start, it stays tuned right, and they rarely quit in flight. And, they have a lot of power.

Try and either buy a trainer with a nylon bolt landing gear setup, or ask someone at the field about modifying yours over. You are going to be landing hard....often. The nylon bolts shear off and saves the fuselage bottom on hard landings. You just replace them and go back to flying if it wasn't a catastrophic landing.

Get someone at the field to look the plane over. Almost all ARF trainers need reinforcing to make them tougher as you are going to brutalize the plane for a while. A little triangular balsa stock glued here and there will make your trainer last longer. The engine firewall is a good place to beef up.

Anyway, it may sound all bad but it isn't. It is just how it is with a trainer. We have to learn on something, and a good trainer will let you learn and have fun. I got my trainer second hand and had the usual bout with hard landings, etc. It has now been repaired and strengthened where it needs it, and will probably last thru a couple more new guys.