Truthfully, almost any race can benefit from pumping up from a higher acreage and then being hit back down. The problem with undead lies more along the lines that the only thing they care about is their elites... and with army in army out it's hard to kill those precious elites.

Conversions are, of course, completely broken. Undead just rampaging across the server, hitting people with army home to get those conversions. You can't really retal against them, sci is practically worthless, acres need to be lost (Other than ambushing... except they can do more damage to you than a few elite kills will do to them).