there are mp5 ptws, they are fairly rare and discontinued so parts/upgrades are even harder to find, we have one on our team and it does very well against longer guns.
i may come across as a ptw pusher but its personal prefrence and you need to way the pros and cons to make your own decision. like i mentioned there are alot of opinions on both and so there is also alot of threads about both. i tell every "new" player the same thing....read read and read some more. this is my first year in the sport and i spend 3-4 hours a day on these forums and others just reading threads about everything.