I voted for Rondo. I like LoT, but if it weren't for the ass-kicking heavy metal/fantasy theme nobody would even notice it. The way your dude/ship moves is really crappy too. Its a great game, but I like GoT a f*ckload more.
Rondo is the best "real" Dracula game Konami ever made. By, "real", I of course mean Drac games before the PS where they turned into super easy "gotta catch 'm all" games that just got easier and easier as the game went on.
Either way I think the arguments about which one "lasts" longer are stupid. Both of these games are ancient, and I still play both of them. LoT more than Rondo, since LoT is more "pick up a play" friendly. Since I mastered them ages ago its hard to tell at this point, but I don't think either of them are that easy. LoT is easier than most PCE shooters, and Rondo is easier than pretty much any earlier Drac game, but both took me a while to finish. If you don't know that all other other (more impressive armors) in LoT are worthless except Earth, you'll have a hard time figuring that out. Also, while it didn't take me too long to clear Rondo, it did take me about a week since Death is hard. If you play as Maria the game is a lot easier, but clearing it with Belmont is tough. Also, I always have a hard time figuring out how to get to level 2'. I always skip straight to 3' when I take the underground path for some reason. Also, I have a hard time remember how to get one of the girls. I think its the nun.
Either way, both are top 10 PCE games.