Battlefield 2 - "2nd level" weapon upgrades?

[GoPodular.com]

I don't know how many of you guys play (the bug ridden and sometimes completely unplayable) Battlefield 2 game, but I need some help with choosing a weapon upgrade.

I have upgraded all classes once, and the assault guy twice.  I can choose two more classes to upgrade to "level 2".  I'm pretty sure I want the 2nd upgrade for the sniper.  I like the first upgrade for plucking pilots out of the air, but I need a faster reload on non-helicopter maps.  That leaves one choice still undecided.  I need it to be good because I won't be unlocking another set for a few months at the rate I play.  I bounce through all the classes depending on what map and who I'm playing with, so I'm open to anything.

What class shows the biggest improvement between the 1st upgrade and the 2nd?