Probably my favourite instrumentals ever(along with the table on Raekwon's "immorbilarity" album) but honestly mate, if I could only choose one rapper's/group's beats and nobody else's, it would be Mobb Deep everytime. It's mainly Havok who makes those beats though I think, but Prodigy also did a bit himself.
Nothing in hip hop, in terms of instrumentals, comes close in my eyes mate. It's hip hop at its rawest.
As for Prodigy, he is certainly one of the greatest rappers of alltime. He was in the game for a long time(and even as a teenager, he rapped and sounded like an adult), he's probably the most underrated of alltime to be honest as he has so much material and is as good as anyone. For me there is no GOAT in hip hop as there are too many styles and different MCs that in the end it can only come down to personal taste. What I'd say is that there is a group of rappers who are all the GOAT in their own right and Prodigy is one of them.