I really like my velitesI am fairly archer and cavalry light though, so that might be part of it.
I have appreciated my velites vs gauls as well - javelines do very well vs the guals cavalry and their swordsmen, and the velites have lots of them.
And they are fast enough to get out of the way of the gaul cavalry sometimes. (Using skirmish mode on them seems to be a little buggy).
I don't bring a lot, but I like to have 2 units of them around vs gauls.
They are more useful vs the greeks I think, who have lots of their own skirmishers too and the slow moving phalanxes.
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