For me FFVI is a much better game than FFVII. Sure FFVII improved the series but FFVI is much deeper than any other FF in my opinion, if you didn't started playing Final Fantasy games with FFVII like most of the gamers and you aren't playing videogames for graphics, maybe you will agree with me.
Kefka >>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Sephirot. Kefka is just one of the best villains ever.