Yeah I went with the DVDO Edge instead of XRGB 3. It can use SCART, but uses a different connector called RGBS (basically a component cable YPbPr+75 ohm rca cable). The quality is amazing.
What someone needs to do is write a guide for which RGB cable you need for each system, down to the exact model. One example is Japanese Saturn/European Saturn.
Pin 1 on EU DIN connector is 9v while on JP/US sync.
Im still looking for a sega genesis/mega drive cable that doesn't produce faint vertical lines on pure colors. Its not as bad as it sounds as I can only notice it on say, the sky in a game if pure blue. Would be cool if someone could make me one, I would gladly pay. If not, gonna have to do some rewiring/soldering.
Emailed a guy named fudoh and he said it is because it uses sync pin, instead of composite sync, and that almost all RGB cables for genesis/mega drive are that.