Yeah, i have to agree, the CSS dualies are ALOT better then their 1.6 counter-parts. In 1.6 the dualies didn't shoot in the center, they shot a little to the left and a little to the right for each gun. But in CSS they both hit in the center and are pretty powerful and fast.
UMP is probably the least used weapon in the game right now. People would rather use a TMP. Some people are fond of this weapon, but i'm not a big fan of it. I like the AK, i'm not sure if the UMP is similiar, if it is, i might have to go back out and try it. P90 on the other hand, now thats a submachinegun i can use.
Might be becuase it was made to be sprayed with...
The Mac-10 is good for close range maps, like office. It hurts but is SO unaccurate
On the subject of SG553 and the AUG. I think(i don't know how many people will agree) But the AUG is a much better rifle.