Which will have the better build up?
Cena vs. Rock. Both guys have delivered some good promos on each other, both men have been outdoing each other which is what a feud is all about and when this continues next year, it will keep me on the edge of my seat to see who gets the last laugh on the promos and with both guys being face, we'll see both guys doing some heelish things to each other at times which will show how deep this feud is, hell Rock cost Cena the match against Miz at WM, did anyone really expect that? Plus the kiddies vs. adult debate is far more interesting than generation vs. generation debates. And between now & WM 28, with the one off appearances by Rock in which he'll obviously do something with Cena each appearance and the Twitter war between him & Cena, the rivalry will just boil even more. With Hogan vs. Rock, Hogan was the one going over the most in the build up by taking him out in the ambulance and pinning him in a tag match, wasn't really exciting at all.
Which will have the better final match?
Rock vs. Hogan wasn't exactly a wrestling clinic but the crowd reaction made the match. With Cena vs. Rock, I don't expect a clinic here either but both men I believe can do better wrestling wise as they are young, fast and have some good moves in their arsenal despite peoples claims that Cena has only 5 moves and of course the crowd reaction for this will be just as huge as Rock vs. Hogan, so all in all I believe Rock vs. Cena will have the better match.
Which will be the better feud overall?
As mentioned above, I believe Rock vs. Cena will take the better build up & match, so Rock vs. Cena.
Which will be the more significant to wrestling's history?
Cena vs. Rock. Better build up, better promos, better wrestling match, kiddies vs. adults, generation vs. generation, PG Era vs. Attitude Era, there's a lot of substance to this while Hogan vs. Rock is just generation vs. generation, that's all and Austin vs. Hogan was supposed to originally happen, so tbh I just can't help but think of Rock as nothing but a replacement. If it were meant to be Rock vs. Hogan all along then I could take Hogan vs. Rock more seriously.
Cena vs. Rock takes all 4 categories.