KUKAs are generally more accurate robots (for example, they don't change continuous motion paths nearly as drastically as Fanucs do when increasing speeds)
Not sure if I understand you correctly, but from my experience KUKAs are a PITA when it comes to continuous motion, as the paths change with the override, not with the programmed speed.
With Fanuc, if you program a motion, the robot will move identically in T1 at 10% and in AUTO at 100%. With KUKA - no way, you won't know what the path is until you run the program with override set to 100%.
That thing about being accurate... Well, I can't really agree on that too, especially that it's possible to increase the accuracy of Fanuc robots using "absolute accuracy" option/procedure. The difference here is negligible in most cases.
There is a couple of things that I find as KUKA's advantage:
1. some heavier robots' designs - without the additional arm in the back, which substantially increases the work envelope. On the other hand, the smaller, hollow wrist robots by KUKA are quite bulky and clumsy.
2. easier setup of many functions and options. This is mostly because the controller is Windows-based, which allows it to use many features of a "civilized" OS. But, again, on the other hand - it can be a cause of quite some problems with KUKA controllers (of which being laggy is the tiniest one).