Though I selected "don't use either", that's not precisely true. I do make a minimal but nonzero use of Type IVs in outlying areas. If I ever get the regional MICs up to level 5 I might recruit a general or two just for fun, but odds are I'll achieve the campaign victory conditions (finally!) first.

I'm playing 1.0, so maybe this changed, but I'm quite unimpressed by client rulers, primarily because they can't sally on the first turn of a siege. I've read that they can sally, so I infer that the script lets them move after the siege has been in place for a full turn, or something like that. So RPing a Judean client state was an error - now I have to keep a ~half stack field army next to the city to trigger a battle whenever the next Ptolemaic suicide squad comes along.

Seeing the client general in combat - he's OK, nice big unit, but not as good as the heavy cav I can recruit normally.

The ability to recruit generals isn't a big deal in EB; I always have lots of FM, and if there's a temporary shortage I'm happy to just sit in place until the next teenager finishes his education to lead the next offensive. EB is an incredibly long campaign, no harm letting 5-10 years pass uneventfully. If the recruitable generals were significantly different from normal FM they'd be more appealing. So I could see KH using IVs to get cavalry generals, or other factions getting infantry generals if that's possible (Gallic provinces offer those, right?). From what I've read, Casse must love IVs...