A friend back long ago had a 65 Corvair, and it was pretty nice. From 65 on when then put the double-jointed axles in, it was a good handling car, and reasonably safe. You can argue about Nader all you want, but the earlier design was pretty deadly. As I recall, it wasn't just the oversteer from the swing axles, but the fact that they had little or nothing to hold them from drooping, and combined with a too-soft overall suspension and inadequate stock tires, it allowed the rear wheels to tuck under the car and literally vault it over. VW's did much the same thing, but less readily, because they were sprung more stiffly and had less horsepower to push them around. It was apparently possible to flip a baseline early Corvair at 25 miles an hour in a sudden lane change. They also had a few other teething problems, including a front axle problem that contributed to the overall tendency to spin out (I can't remember the details on that one, but I think something actually collapsed there), and a gas tank design that was a little bit too prone to blowing up in collisions. The early Corvairs also had a serpentine V-belt that failed easily, leaving the engine with no cooling.
And of course, as usual, it wasn't so much the bad design that killed Corvair as GM's attempt to cover it up or to deny it, and the all-too-typical corporate attitude that it's cheaper to pay for a few deaths than it is to fix the problem. By the time they did fix the problem, it was too late to revive the model, because "Corvair" was by then about as reputable a name as "Edsel.". They should have re-badged it as a little Pontiac with a different name.
Corvairs of the earlier type could be made fairly stable with the addition of a stabilizer spring beneath the swing axles, to limit their downward movement. The 64 came with this, I think, and it could be retrofitted to earlier ones. Suitably modified, swing axle Corvairs were pretty successful in racing, but this doesn't mean the regular ones were safe, because of course they were not fitted with stock shocks and springs, and 2-ply tires, as the consumer models were.
I'd stick to the later style, in part because I think they're better looking. Actually, although some details nowadays look a little dated, I think the 65-69 Corvair was one of the most harmonious designs ever to come out of Detroit.