In deciding on my unlock I realized that it's really about what role I intend to play.  I used the Assault kit the most in just getting a feel for the gameplay and getting points.

That said, I prefer to play a bigger part in the game than running around counterstrike style.  

In a given server, assuming not a whole lot of teamwork, which is the more useful kit (also assuming a competent team player is manning it).

Special Forces or Support?

Again, I mean playing these roles as they are meant in the tactical sense, not just for "the gun".

Opinions?

I tend to split my time between anti tank and support.

The support kit is really great when it comes time to get that stupid sniper off the roof, you get endless grenades by resupplying yourself.

And on the construction site at sharqi, the support kit allows you to hang around blowing up people as they spawn almost indefinitely.

The DAO of the anti tank kit and the belt feds of the support kit are my favorite rambo guns in the game for putting people down.

What about the medic class??  It's an easy way to rack up the points and you can always heal yourself if you run into some crap.  Just being able to revive people helps your team out tremendously.  Try that out, especially since you've been assault and the guns are either the same minus the GL or very similar.  

Honestly every role is important to the team when played correctly. That said, I've only played assault just long enough to get my veteran badge and I haven't played it since. Support and medic is good for teamwork points. Spec ops is fun to blow up assets, vehicles, and jihad. Anti tank is good, but the weapons for it kind of suck.

If you are gonna go for a class that can be beneficial to your team I wouldn't necessarily choose Special Forces.  Yes blowing up the commander toys is nice but can the time spent running to the enemy base be justified.  I have over a hunderd hours in each of the 3 support classes.  Engineer,Medic, and Support.

I find support and medic to be equally useful in MOST cases.  Especially when there are alot of ground forces.  The only time I really find an Engineer to be useful is playing big open maps with alot of armor. - and only if you are driving armor yourself and you can park next to other tanks and repair them on the fly. Other than that Engineer is pretty much useless, not to mention you get owned on the ground by people playing other kits because the shotgun blows unless you are up close.

I usually play support, medic, AT and sniper.  I'll do assault and engineer once in a while.  

I've been playing mostly support and engineer.  

It's amazing what you can do for the team if you truly play engineer.  As for the shotgun, you shouldn't be running around looking for combat with it, you should be repairing vehicles and hanging back and defending strategic points of the map with the mines.

I held the Wake North Base solo for an entire round (full server and no lack of attempts to take the flag) by alternating between support (dropping ammo for spawning as engineer and gunning runners) and engineer.

The downside is that you don't get to run and gun much.

I guess alot of it depends on the map.