Totally agree, the Scart board, for me, gave a poor picture for Sky+, switched over to the JS RGB-VGA box and it was a magnificant improvement.
The XBOX looped through the SKY box to VGA gives a very good picture but if you have a modded one, switch it to NTSC and turn on the HD resolutions in the MS Dashboard and plug a Microsoft HD component cable into your screen and you will be amazed.
An alternative to a component switching box is using your amp if you have one and its got the relevent inputs.