I agree with forumguy, the micro's are very twitchy due to their inherently low weight and tend to be much, *much* harder to fly than the larger glow powered models. Also, flying them indoors low to the floor and walls tends to generate odd air currents you typically wouldn't see outside with the larger models. These currents again make micros difficult to keep under control.
The reason some advise against beginners staying away from the micros is because of the frustration factor. Take me for instance, I've always wanted to fly model helicopters. I'm an experienced R/C glow powered car guy (1/8th scale) and I recently decided to give it a go. So, a few weeks ago I got my Hummingbird kit and a simulator along with a pretty nice computer radio (trememdously more powerful than the 4 ch job they try to sell with the kit). My goal was to learn a micro and if I still though it was fun, sell my car stuff and get a .30 Raptor.
After about a week I'm hovering stable with the simulator and I can even nose in hover. The only time I crash the sim is when I start getting silly and goof off doing stupid tricks I don't know how to properly perform. Anyhow, thinking I've got a real good handle on the flying thing, I finally crank up the HB in the garage. (Up to this point I hadn't touched it). Well, like you I've already gone through a set of main and rotor blades! I still have a bottle of CA on the table ready for the next smash into the lawnmower handle or shelves! I lost count how many times I've repaired my blades. I still can barely hover the HB! In the sim it's a piece of cake, but the real thing is starting to make me mad. Last night my frustration reached an all time high and I almost threw the thing in the trash. The reason the "experts" advise against beginners flying micros, is because of people like me...
Helicopters are hard enough to fly, but throw in a twitchy micro and it could easily scare off potential hobbyists!
I have a new appreciation for those guys in the videos who hover down a hallway with the thing barely moving side to side more than a couple of inches!
I'm digressing. While I'm certainly not an expert, I don't think you have a thing to worry about. If you are hovering through a LiPo pack for 15 minutes straight you're doing fantastic. I bet if you were to fly a .30 or .60 sized machine at this point, you'd be able to do it sitting down in a lawnchair drinking a beer!
Keep up the good work. The hard stuff is behind you! Now start learning to be comfortable with the heli in different orientations and you'll be doing 3D with a CP model in no time! KEEP UP THE GOOD WORK....I'M ENVIOUS!