I would be one of the ones who consider Peart's talents to have legendary status easily. However, his lyrical creation is too corny and gets some negative for me.
Steve Vai is absolutely up there in terms of talent, but is a guitarist more talented than a drummer? Hard to compare apples to oranges. Yngwie Malmsteen in terms of pure talent could be better than Neil, but again you are comparing different types of instrumentists. I am a drummer myself and even though Peart's pieces are not necessarily super challenging except for "La Villa Strangiato," they are super fun to play on the drums. You definitely have to think a lot more instead of reacting to easier drum songs, but all the top Rush songs are playable every time I play the drums. He gets a ton of credit for me for the creation of his famous drum fills, but he also gets a lot of credit for the songwriting process since he was integral to the band.
He cheques a lot of boxes and I would give him the nod over Portnoy in many categories, but Portnoy's challenging elements in his drums simply blow Peart's most difficult out of the water quite easily. By simply talent, Neil wouldn't even be the best drummer, but makes up for it in a number of other ways. And no, none of the drummers for Led Zepplin, Yes, Zebra, Genesis, King Crimson, Pink Floyd, and "other classic rock band insert here" comes close to Peart of Portnoy's drumming. Keith Moon maybe, but what made him very interesting is how unique of a drummer he was. Not a lot of hi-hat, but a ton of tom playing and cymbal crashing. Not necessarily more difficult or particularly challenging compared to the other two drummers, but just unique in the grand scheme of things. E: The most modern-day drummer that could challenge these two is Danny Carey from Tool.