I actually own the ROTD SEGA CD itself. I also have ROMs for WB and ROTD.
I personally wouldn’t bother with the SEGA version, but for everyone else it’s a good choice. The SEGA version had scenes removed and a higher rating, which dissapointed me greatly, especially as my favourite scene got deleted.
However the voices and one or two extra goodies is a plus, as is the slightly better Adlib music for you folks (though for me the Roland MT-32 disk version music is supreme).