Wow! you could get some really long replies with that question. I don't really think you need to know the answers to all of those questions to choose a good 3D helicopter, the market is full of good choices. Just remember you really do get what you pay for, this doesn't mean that the cheapest helicopter on the market isn't any good its just affordable.

If you have money to spare then go with a Fury Extreme, if the budget is tight get a Raptor 60, I know Guys that have plenty of money but fly Raptors any way just because they don't like the idea spending $300 and a whole weekend to repair a Fury.