I've used old and boxy Quantum slaves, cheap Yongyou/Amazon/Chinese stuff, and my current PocketWizards. Never had issues with timing, but my flash sync has been in the normal range, 1/250th, 1/60th, 1/400th depending on the camera. Make sure you get the oddball sync cords for the Vivitars!
What I have found that's a big issue - the cheap Chinese stuff I tried doesn't sense the trigger on some of my older gear. RB lenses won't fire it consistently (if fact only my 90mm will trip it once every 5 or so pops); my Minolta spotmeter F won't either. My older PC-equipped smaller shutters, like copals on 4x5, prontors on folders, etc - will fire it just fine.
I think the RB must have more resistance in the circuit or something (ever see an RB flash sync? Big butch brassy looking parts). No clue on the spot meter. Just something to watch out for.
As far as synch voltage, I only use one receiver, and use peanut slaves and similar on the other units. Sometimes it means rigging an extension to get the peanut into the lit area, but it's generally less hassle than powering multiple receivers - I've only needed multiples for things like shooting in a factory and having packs strung out among machinery and things like that, or having packs and heads outdoors blasting through windows.