Hmm, Dylan1CC, I think there may be a problem with your games. I highly doubt that DGen is overhyped because it runs my games flawlessly.
After I read your post, I went back and checked my copy of Gunstar Heroes. Perfect. I didn't even mess around with the settings at all and I had no problems, not even the ones you mentioned. I also retried Revenge of Shinobi once more, this time trying it with all of the different region priority settings. I could've sworn I had already tried them all in the past, but this time I found one that runs it the same speed as PSPGenesis, but smoother.
So, as of now, DGen is back to being my top --and only-- pick for Genesis emulation. Quite honestly, while PSPGenesis was impressive (especially for such an old release), it stuttered a lot.