At least Uterus always has action. As for GVs, and killing GVs, it is without doubt the best map. The problem with Uterus , back then, is we were getting it all the time. Sometimes two at a time.
The reason why its such a good GV map is the spawn placements. Many bases have numerous spawn in/outs. Pizza, on the other hand, usually only has one spawn in/out a base, if that, and it seems like the spawns are always going to your own base.