[tjwmason]

My understanding is that the Harriers crash rate had a lot to do with unbalanced thrust vectoring and the fatal roll that this created on landing.

Much of the problem was sorted out. When the Harrier first leapt onto the scene computers could send little white blobs around in a game of quasi-tennis but not much more. As the Harrier was around for longer, it could be fitted with computer systems which allowed much better management of the thrust, and thus far better safety.

[Tallguy]

Most of the Harrier problems were sorted out with the AV-8B. More powerful engine & avionics plus a greater percentage of composite technology in the airframe.

You also can't compare accident rates of single-engine and dual-engine fighter aircraft. The former will always be higher, for obvious reasons. So far all STOVL jet fighters are single-engine.