Having ridden both today… both are phenomenal, but I have to say that perhaps unexpectedly, I would personally vote Hagrid’s.
Don’t get me wrong, VelociCoaster is an excellent, excellent coaster. The second launch, top hat and mosasaurus roll are all absolutely top-dollar elements, and there are some other very nice elements sprinkled throughout the ride. The ride has a good sense of speed, the restraints are brilliant, and it’s overall a really excellent coaster!
However, Hagrid’s is just incredibly, overwhelmingly fun in quite an indescribable way. The ride was faster than I was expecting and had punchier launches than I was expecting, but my overriding feeling towards Hagrid’s is that it’s just pure fun and makes you laugh hysterically and smile throughout. And for me, fun wins out.