I'm using SCART for the Framemeister on a HDTV. If you're not willing to fork out the cash for a Framemeister, you can use a generic SCART to YPbPr (Component) box in conjunction with a Neo Geo SCART cable. It won't look as good and it will fully depend on your HDTV's upscaling capabilities but it beats Composite or S-Video any day.
https://www.amazon.com/SPECIALTY-AV...rd_wg=BokiY&psc=1&refRID=WAH62FJWFR8SFR9ADWNQ
Keep in mind that SCART itself is a European standard and there is a Japanese equivalent called JP-21. Both are equal in quality but you can't mix them up since they would damage your equipment, stick solely to SCART and avoid anything JP-21.