Just thought I would chime in here since I have used the A-Neuvideo processor you linked as well as DVDO solutions.
You can find those A-Neu processors on ebay for around $140 or less (I’m selling my own there since I replaced it with a DVDO machine, but I got it off ebay originally as well for around 140 from another seller). In terms of performance, I didn’t have it hooked up long enough to do extensive testing. The one thing I can say for sure, is that it was able to make a very unstable SNES 3x signal that I couldn’t get my capture card to work on without extreme stutter, play perfectly smooth and upscale to 1080p. So it certainly works as a signal conformer to some degree. I didn’t notice tearing or significant lag, but I really didn’t test it much, because I ended up getting a dvdo edge probably a week later. The main thing it lacked that I (knew about beforehand, but later decided I wanted), was pan/zoom functionality.
I have used a DVDO edge and am currently using a DVDO duo, and both can make higher than 2x work for sure. With the DVDO duo I have everything 240p working at 4x and I prefer that. Sometimes the SNES was dropping out for a second at completely random intervals (sometimes 30 or 40 minutes would go by and then a dropout) I haven’t sat and played it long enough since tweaking the settings last to see if I have fixed this. I personally was able to get two dvdo duos from the same seller on ebay for around 160-180 with some random cables, each. This was some kind of business liquidator who has sold a few of them during the time I was looking. Unfortunately other than that, they seem to go for closer to 4-500 USD.
I also already owned a Framemeister before ever owning the OSSC. Quite honestly I never use it anymore. I prefer the OSSC + DUO combination, but the price was about the same in the end. I never tried running the ossc to the framemeister… i thought the hdmi inputs on the framemesiter are passthrough only?
The framemeister is really the best option for compatibility of all things, especially since it handles composite/svideo if you need those. The only thing I have still running on s-video is a 3DO i rarely play, but I would still use the framemeister for that. The noise in solid colors on the framemeister really really bugged me on SNES games, which was the reason I ever looked for an alternative.
It really just depends on what quirks you can deal with, and how much hassle you are willing to tolerate for the various options. None of them are perfect. But there really isn’t a single low cost solution if your OSSC doesn’t work the way you want with your display.