Nah, man. It's the best-best Castlevania game. IV is up there for me, too, but that was the first one I played (and it also happens to be the perfect entry point).
I really dislike IV, it just feels kinda floaty and messy in a way that no other Classicvania was, and I think eight-way whipping was bad for the series. I'm a big super-picky baby when it comes to Castlevania physics, haha.
Rondo, though. What a game. It's the only 16-bit 'vania to nail the physics in the same way manner as the NES games (well, the good ones), it adds a few new twists on the gameplay (backflips, dude! backflips! extendo-whip inputs!) and it compliments them with some of the most ball-bustingly difficult level designs in the history of video games. If it had been an arcade cabinet and I needed to punch in a quarter for every death, I'd have singlehandedly financed the development of Symphony of the Night-- and yet I couldn't put the controller down, nor would I ever give in to temptation and play as Maria to make things easier on myself. The game was too tight, too much a joy to play for me to quit.
And then you realize every level has a secret exit that leads to an alternate stage and there's a whole other game still lying in wait... and it's even harder. Rondo of Blood is game with deceptive amount of meat on its bones, and it's all your favorite cuts. You grill it up and eat it and you can't believe how bloody it still tastes and when you're done you realize your mouth is bleeding because the steak was full of broken glass but you can't really be mad about that fact because you just ate the best steak of your life.