I just tried RA 1.2.2 and it royally fucks up the vsync with Genesis Plus GX; in this instance it's preferable to use the standalone version. Why? Simple. It doesn't run a perfect 60 fps all the time in the recent RA, like when the levels go by at 60 fps, there are occasional dips in the framerate, it's really weird. The standalone never does this, however, meaning 1.2.2 is worse speed-wise than 1.0.0.2, so I might have to roll back to that once since a lot of things seem to be broken. Also, as for the Snes9x GX vs. Next, there is one thing the GX version never ever fixed, but Next did; the infamous tinny sound glitch. I believe that this was an error in the libogc library as the GX menu used Sinc or Hermite interpolation at 48 kHz whereas the Snes9x emulator itself ran with Gaussian interpolation at 32 kHz, hence the tinny sound. To get around it, you'd have to open and close the menu till it went away; Snes9x Next however, does not have this issue. Yes, neither emulator is perfect, but at least Next doesn't struggle with Star Fox or Final Fantasy VI, to name a few games.
The tinny sound glitch and how it handles frameskip is a deal-breaker for me, I'm waiting for a standalone port of Snes9x Next on the Wii, it can be done, just a matter of it being made with a GUI. I should also note that mGBA Wii is far superior to VBA GX in every way, 95% of GBA games run at full speed, only a small handful don't quite run 60 fps, but everything else does, no jumpy speeds or audio crackling.
I'd love to see someone try to prove that VBA GX is better in terms of emulation and speed/audio than mGBA is
Edit: Oh and Snes9x Next rarely has code dumps.