Any heli hit will affect its stability to some extent. The good helis (the ones that fly better) tend to break even better !
The big decision is what kind of heli flying you are looking for ? If you are looking for indoor flight, the Lama v5 4 channel one is a good choice.
If you are looking for outdoor ones, I would suggest you start with a Trex 450 (or something similar like the Mini Titan).
Remember that all these helis will break if you crash/hit anything fairly hard. There is no heli that can take a lot of abuse. The trick is to reduce crashes, by following some simple steps.
Step 1: Buy a simulator, and practice heli flight on it, until you can not only hover it, but also fly it around comfortable, and hover "nose-in". Nose-in hover (making the heli stay hovering in one place, with its nose pointed at you instead of the tail) is a pretty good test of whether you are ready for real flying. When you can do nose in hovers comfortably, fly a real RC heli.
Step 2: Do not fly in congested areas initially. Fly in as open as area as you can find. Even indoors, fly in the largest open area you can find.
These two simple steps will save you a lot of money and heart-ache
