I know we've strayed from the topic in hand, but interesting conversation however.
A point to note is that I was failing miserably on the Metro challenge to get the F2000. So I played on one of the custom / personal servers that had 200% / 1,600 tickets instead of 800. I'm sure there are some still around (if not more). Even then, I think I only grabbed my second assist ribbon with literally the last kill (my assist) of the game, seriously... God I'm rubbish.

So somewhat cheaty, but it's such a pain in the a*se challenge.
With regards Assault, I have levelled up the ACE 23 to max, and it's a class weapon. Love it. But even though I do love the Med-Pack and Defib combo (especially on Locker... ribbon-tastic there) I can't get away from Support being the best and most fun class.
I use the other ACE gun there - although I did like the Mtar - along with Weapon Crate and C4 Explosives. C4 is the best thing ever. Last night I must have destroyed five or six vehicles with it in one match alone, and the best thing is you throw down a weapon crate and give yourself more! Throwing them onto a tank from the top of the bunker at flag A on Zavod... I could never get tired of that.
I agree the health replenishment is great, it's just that, if you wait 30 seconds or so it'll replenish anyway - ammo won't so I prefer that.