This isn't just high and mighty regulars giving their high and mighty opinion either. Most people here went through the exact same thing themselves and are speaking from experience.
As far as I'm concerned, if you want to play an old console on a modern set, you've got a few good options:
1. Buy the premium stuff that is made for gaming that other gamers have vouched for ike the OSSC or Framemeister.
2. Emulate and forget original hardware altogether.
3. Use composite or S-video directly on your HDTV.
Just don't waste your money on some half-measure piece of non-gaming hardware that is designed with some non-gaming application in mind. If you think "well, I'd rather gamble $25 dollars on some unknown hardware that
may look
slightly better than composite," well.... I don't know what to tell you. That's likely $25 wasted. It will probably lag and still not look how you want it to. And then you'll realize that it isn't much better than composite anyway and you'll go back to allowing your HDTV try to resolve the composite source.
You're just better off letting the brand-name HDTV try to do its thing with the composite image than to trust some other random piece of hardware that no one has ever heard of.
And if you think there is something we missed -- some sort of $25 solution that you think looks good because you took a chance on it and feel like it was money well spent-- then post some screens and allow others in on the secret. But don't just say "hey this thing is a good solution" without pics or evidence and expect everyone else to not immediately assume it sucks without more information.
When it comes to image quality, if you're going to be cheap about it, just be cheap all the way and use options 2 or 3 above. If you want a good image, then go the other route with a CRT or a good known product. But whatever you do, just don't drop a few bucks here and there because you feel like dabbling in a different flavor of shit sandwiches for a while. It's a waste of time and money and poor image quality is already possible right out of the box.