If you're like me, having an all-in-one solution for playing practically the entire SNES and Super Famicom libraries would be ideal. Although I generally don't support piracy, with the way the retro gaming market has exploded in popularity and the fact that prices have gone way up, it's nice to be able to play games that one wouldn't be able to try out otherwise. Besides, not only do the original developers not get a single cent out of the second-hand market, but people can always try a game out and buy the game afterwards, like a homebrew game for example.
As for the actual cartridge, it can play just about every single cartridge in the console's library (99.8%, in fact) without any compatibility issues whatsoever. Although I haven't tried out a particularly large amount of games so far, every single one that I knew didn't have issues (i.e. Nintendo Campus Challenge '92) has worked effortlessly and are virtually indistinguishable from the original cartridges. From Super Mario World and Hong Kong '97 to Stunt Race FX, they all work perfectly.
Even though this cartridge can be quite expensive, I implore you, if you only want to buy one Super Nintendo cartridge in your life, make it this one. I'm sure that even the obscure Japanese mappers that aren't currently supported can be patched in via firmware updates. The cart is also very customizable and the settings and menu can all be tweaked to any person's individual tastes and preferences. This cart is amazing; buy it now.