Initially the low previous owners figure does look good but I'd much rather four previous owners that maintained the vehicle well than one that spent all their money on buying the car then had to skimp on maintenance.
Overall condition/servicing and price of the vehicle is most important, low previous owners is nearly a bonus as this doesn't guarantee condition.
You often see Porsches with lots of previous owners as its for some a bucket list car, couple of years then sell it on. I'd imagine the 350z and 370z fall into that category for alot of folks, ie for a good example not overly cheap to buy, tax or insure etc. Circumstances change and a more sensible vehicle is needed.