I agree with Seamus... Cap Navy is the better of the two pieces of Capitol. However, Ground does alright.
Scorpions (smgs), Rangers (LMG's, grenadier and Pistols), Strikers... They can do the job well enough.
In the environment you mention, all three elite choices work. For the Grunt feeder units, LI and dogs are the best. If you want a fodder squad, Freedom Brigade with up to 3 lmgs is nice too but they die quick.