I have a Duo-R, modified by someone here, with S-Video out. I use that most often. I also have a TG-16 I keep in a travel case, though the last time I took it anyplace was... 2005? 2006? It's been a while. I have a Duo, US model, I bought new, but I don't use that, since I got the Duo-R modified.
I used to use CRTs. However, the past decade or so, nothing like that.
Years ago, I thought I'd need to get an X-RGB, but I never had any video issues, so, I never needed one.
I run the Duo-R through an S-Video switchbox, along with a Genesis and a few other systems. All that feeds into an A/V receiver, which handles the S-Video to HDMI just fine, and outputs nice all channel stereo, fi I want it. I was actually messing around with Splatterhouse 2 and 3 on the Genesis 2 weeks ago, still works fine.
I size my screen to 4:3 for these games and play with grey or black bars on the side. I don't like playing games distorted and stretched out.
In the future, if/when I need to upgrade my receiver, it will be difficult to find another with S-Video, though they are still out there, just less. During that time, I may need to go with some older models with the S-Video inputs, or get an s-video-to-HDMI adapter, and feed it into the receiver as and HDMI input.
But, for now, it all works just fine. The Atari 2600 I hook into a coaxial A/B switch, and the TV outputs the sound to the receiver. Yep, Atari 2600, in FULL MONO!
.