I'm using RA's nightly build and update ones a week in the hope they repair it. Yes, I use the wide core as the default Sega core, cause I prefer RA over stand alone emulators.
Ok, so ive tested the RA GenPlusGX Wide and the results are not good IMO.
1. Playing Genesis games, the left side of screen is crippled while scrolling to the right.
2. Playing CD games, there is a mirror effect on both the left and right side screen making some games nearly unplayable.
The RA 1.8.8 included in the current plugins pack works very well without issues. It is a shame the RA Sega GX core hasn't got proper attention over the last 12-15 releases to a point when loading the core itself, the result is black screen freeze.
The RA Hexaeco GenPlus GX Wide core is far superior BUT does not support CHD loading. Although it does play games correctly without mentioned issues.
All things considered, if you need a second option to the Official GX stand-alone, the BEST alternatives for Genesis/CD games are Hexaeco & RA 1.8.8 which are currently in the plugins pack.