Definetly parts availablitiy and the trex is one of the best flying 400 size helis out there ( if set up right). You will pay alot more up front to get a trex in the air but once you do you will not be disappointed at all. My first heli was a $300 RTF heli that I got a few years ago and grant it that thing flew ok but once I built my trex it was like night and day