I just bought a P4 and I noticed two things off the bat. First is the throttle response seems very sluggish (in all flight modes) compared to my P3P. And second, the motors have this kind of weird sound when you go in full forward flight. Then, something else weird happened. I went to land the AC and right before it touched the ground it started to jitter from left to right. It kind of scared me for a second or two. My P3P has never done that. They also say the P4 is supposed to be faster in forward flight in sport or non GPS mode but I wasn't feeling it. I was hoping this P4 was going to "ooh and awe" me from the very beginning. Not hardly, hardly at all.