Your experience and knowledge seems similar to a lot who have bought the kits. A VOM (Volt ohm meter) is a required tool. Even in the 70s not many had oscilloscopes.
The 8800 is nice because you can see into the heart of the computer and manipulate it on a very low level. The 680's front panel does not show nearly as much.
I'd like some other kit builders like Paul or Geoff to give some insight here.