Funny the turns some of these threads take.
CVIV vs. Rondo. Hmm... Well, first all, as some have said, CV4's atmosphere blows Rondo's away. Somehow it's so immersive that it makes you alternately nervous, scared, elated, and a whole bunch of other things.
Graphically yeah, it's gritty. But if you're going to Dracula's castle, I dunno about you, but I wouldn't expect it to be the shining portrait of opulence that SoTn and Rondo make it out to be. I mean, sure it has its moments of said opulence, but it's an old craggy castle! And the graphics certainly reflect that in the highest degree!
Musically, the game is amazing. The fidelity of the tunes and the fact that they're ARRANGED! You can actually pick out string parts, organ parts, bass lines, tympani rolls, etc! The poster who said there was nothing memorable in CV4's soundtrack is crazy! There are SO MANY great pieces of music in this game, and while Rondo has a great soundtrack too, it doesn't help to immerse you in the game the way CV4's does.
I LOVE Rondo. I think it is definitely one of the best games in the series. But comparing it to CV4 is like comparing Goodfellas to the Godfather Trilogy. Goodfellas is a fantastic movie, but The Godfather Trilogy (like Castlevania IV) is fuckin' EPIC!