I bought a new VGA box for my Dreamcast (specifically the Retro-Bit one) and the difference in quality is massive, with the previous one the VGA output was super noisy, and all this time I assumed it was my TV that had crappy VGA support, but no it was my VGA box that was a total piece of shit, now it's really clean and sharp.
And of course I switch to the s-video out to my PVM for games that support 240p. Best of both worlds!
Careful with that box though. I owned it and the switch is made with very fragile plastic. Speaking from experience, it takes very little to break it.
I agree with you though that the video quality is superb.