Glo,
Your question about landing speeds is a good one.
The last few feet as a jet powered lift aircraft nears a surface are both complex and critical. There is the ever present risk of Hot Gas Ingestion (HGI) as well as quite complex flow around and under the aircraft that can lead to 'suck down' and/or loss and deterioration of control.
The Harrier had some quite challenging characteristics in this area, although the fact that it was able to enter service without much artificial stability augmentation was a great achievement by the people who designed it. You probably know that a key to this was controlling the 'fountain' of air generated under the aircraft, hence the use of strakes, airbrake and on the AV-8B, a separate air dam.
The best way to avoid problems in this area for the Harrier was to land 'firmly', and so get through the critical 'near to ground' area as fast as practicable. Hence the sometimes firm landings. Although it's worth noting that the vertical velocity of these was still way less than is normally used in 'cat and trap' operations.
Fast forward to F-35B. The team have used design tools and test rigs that didn't exist in the 60s when the Harrier team did their work. That has given the F-35 team a much better understanding of how the jet operates close to the ground, and this has paid off. You'll see from the videos that they are using the inboard weapon bay doors as 'strakes' during vertical landings.
Another major difference from Harrier are the flight controls. F-35B has a 'rate command' system, which reduces pilot workload, but it did, in the early days, lead to some 'rebound' on landing - look up some of the X-35 videos that are out there. This appears to have been solved now.
Just a final offering - this area of the JSF design was one of the most critical and difficult, and has been led and largely executed by a hugely talented team of Brits. Cue for a BIG round of applause, I think.
Best regards as ever
Engines