I haven't used KerbNet much myself. I "grew up" in KSP on Remotetech and it made a whole lot more sense to me than KerbNet did.
However, I always play with one of these active. Doesn't make sense to me to be able to land an unmanned probe on another planet without either a pre-programmed AP or a comm link for live control. It can be turned off in the settings, though.
My latest save, I think I switched to KerbNet because of a mod. Can't remember the mod at the moment (been months since I played), but it allows me to create separate bands and segregate KerbNet into more manageable groups (LKO CommNet, Mun Relay, Duna Relay, etc). Great mod in my opinion.