Which provides better quality graphics: S-Video or RGB?

I currently have a Jap system running through an RGB cable. Is it worth dishing out the cash for an S-video mod?

second question: If you play games on a European system, are there boarders on the top and bottom of the screen? This is a problem with most Euro-trash (PSX etc). If so, is the speed of the game the same as on US/Jap systems? As European machines are 17.5% slower....
Thanks

When I posed this question in usenet (albeit for a Dreamcast system) they said that RGB is the absolute best.

S-video is good, but RGB is the best. No need to waste the cash.
-nick_th_fury

As I'm in the UK I guess I'm in the best position to answer your question about boarders etc. Any game on a UK (european) spec machine will play with boarders and run 17.5% slower than a US or Jap spec system unless the programers specially program a game to run on a PAL system. As all Neo-Geo games are exactly the same if you play one on a UK system it will have the boarders and run 17.5% slower.