Yaw had to be carefully controlled during the decel to the hover as getting out of balance, and inducing large side slips by decel'ing out of wind for example, could result in Intake Momentum Drag (IMD) which would induce a extreme, and normally uncontrollable, yaw and roll which was nearly always unrecoverable unless caught very early on. We had what was basically a small weather vain on the nose of the aircraft and so long as you kept the vain straight i.e into the relative wind you were fine.
Once in the hover later generations of Harrier, with SAAHRS (akin to helicopter stabs although I've probably got the abbreviation wrong, it's been a while) where fairly comfortable to fly, but I would say it was never easy and required you to always be on your game. As you correctly observe the Harrier could bite, and bite fast and could very quickly go from all fine to 'Oh S&@t!!' especially for junior guys new to the jet.
As for did the best pilots go the Harrier.......absolutely!
