MP varieties are some of the smallest airsoft varieties. In fact, I would even go so far as to say that they are the smallest guns around, and the only thing I can do when it comes to size would be airsoft guns. What are the benefits of using a small air gun, as opposed to a large one? I'm going to get into that now, so you can have as much experience as I do.
The great benefit from using an MP style gun is that you can move freely. If you have a large piece, it can be difficult to run fast, and it is easy to beat your opponents. By using MP, it is much harder to beat, and you can easily change positions without much worry. Of course, you still need to have a lot of speed in your body, but no matter what, it is always easier to move if you do not hold too many things.
Another thing to keep in mind about MP 6.5 creedmoor ammo is that unlike real MP5s, airsoft MPs can also work long distances. Cheap doesn't have a lot of range, but if you get a really good MP variant, you'll find that it gets a distance equal to the big airsoft guns. So what is the point of finding something that is not only expensive, but also consistent, if it is going to delay you?
Because of their size, MP5s are generally cheaper than their larger counterparts. You can save a lot of money by going the MP route instead of using a traditional gun, so you should definitely consider picking up this type of air gun.