I've fitted a SimonBBC unit (inc. new coil) to my 69 S2a, to replace a worn out mechanical one, and it works great. Timing needs tweaking beyond normal settings, but engine runs like a sewing machine despite dicky carb (now replaced) and now a dicky fuel pump. Dizzy doesn't look much different once fitted, so only a bad thing if you like point fettling.
Down side I guess is that failure is likely to be fatal, with little hope of roadside bodging to get home - but that applies to any more modern vehicle as well!
I'd say go for it...