Finished building & tuning my 3.6" quad and got it flying over the weekend.
RTF weight is about 29g with a HK350mAh 1S battery pack.
It wasn't flying well at first. The motors have too much vibration and the weak arm causes them to vibrate in flight, and created a lot of fluttering and crashed. I had to reduced gyro gain too much to fly. Finally I added 2 bars on the frame, and balanced the props a bit. It flies a lot better. It can hover hand off for quite sometime.
The vibration from the motors also affect the gyros. I already have two pieces of 4mm foam tapes between the gyro (Wii board) and the frame) but I think they are not enough.