The UMP45 is a GREAT gun for beginners. I'm glad it's in the game.
Only noobs get to call guns "noob guns". If you're good at the game and say the UMP is too easy to use, what's the problem? If you don't like using it because you need a challenge then use another gun. Or you can be honest with yourself and admit you don't like being killed by that gun. The fact is, if you're so good at the game you wouldn't be killed by the noob using that weapon.
The guns in this game are extremely balanced. The ONLY real advantage the UMP has over the Vector is it's clip size. Anyone worth their salt will do just as well with any gun. If you don't, maybe you're not as good as you think.
My point? If you're calling anybody a noob for using ANY weapon in this game, YOU ARE THE NOOB. Get better or STFU.