Just beware if you're playing on a server that the server must have this mod for you to use it, if the server doesn't have the gravisuite on it, you're screwed.
For me I find the MPS jetpack going way too fast, which there was a proper way to control the speed of it, but since you always fly at same speed no matter what the tweaks you can make to it, I stopped using it, I prefer the Morph bat mode for building purpose its perfect, wish there was a better alternative to it...