velite glads (brutii) are pretty awesome.

12 attack, 7 charge, 14 def, excellent morale (+6 bonus i think?), and best of all... 2 hitpoints!!!

armor is low at 7, but they're pretty awesome shock troops, especially since roman cav are not so great.

the other glads aren't as useful. they're slightly better than velite (14/4/14 and 12/7/14), but by the time you get them, you're better off getting the ihgh level roman cavalry (level 4).

Imagine they'll be necessary in desert combat, however (assuming fatigue operates in the same fashion in RTW)