Glad I'm not a fanboy then...
SignOfZeta: The Sega CD version of LoT had its difficulty greatly reduced (I guess people thought the original was too hard), the soundtrack was changed (it sounded similar but it was wussed out a lot), the sound effects were quite grating and out-of-balance with the music (easily fixable on an original Sega CD but not so on the model 2 setup), there were a few things taken out (probably to aid in reducing the difficulty), and the graphics...this is where it took a dump...dithering everywhere because they couldn't keep up with the original's colour spec, and the game had a lot of flicker (especially in the ice level) and quite a bit of slowdown (especially in the underwater level). Even on "Super" difficulty, I had no problem whipping the Sega CD version's ass seven ways till Sunday. I've yet to beat the original version on Super.
What really kills the Sega CD version for me isn't the gross dithering, the weak-ass soundtrack, the unbalanced sound effects, the slowdown, or the flicker...it's the wimpy difficulty. The game is a cakewalk. The original version WILL hand you your ass on Super even if you're good, but if you know the game (if you can beat Hard on the original without breaking something), you can crush Super on the Sega CD version without breaking a sweat.
And yes...I own both versions.
There's only one other very minor gripe about the Sega CD version...where's the friggin credit scroll at the end???