I have one and tried it. I cant say for certain, because the options and settings are all... different. I dont know if its because of the newer hardware, but I dont have the settings I used to have. Either way, I feel like the best I can tell you is: SNES/GBA games run... slightly better. The most I can tell is that they run just a noticeable difference better. But if you ask me, I think that the emulators running on the native 3DS hardware would run better, since the DSTWO+ relies on internal cart hardware and DS mode.
Now if the Supercard team could come up with a way to allow the DSTWO+ to run emulators on the 3DS hardware in 3DS mode... we might have a viable solution for those of use who haven't gone to the trouble of installing CFW, RxT, or .cias for emulating. This cart was meant to be an all in one solution for the DS and 3DS. When reality hit and the cart surfaced, it was basically a slightly beefed up DSTWO that can also launch GW software. This might have been much more popular if it had been released a few years ago, right after all the other carts got blocked and GW was just getting big. But now? I dont see why you wouldnt just use CFW, especially after using it.