While I typically use Nestopia or FCEUGX for NES emulation, I am prone to playing sessions fairly often in MAME too.
Why?
My first experience with the hardware was in early to mid-1985 when a local grocery store picked up a PC-10 machine. It's quite a nostalgia kick to be able to play SMB in the form I first remember seeing the game in. It doesn't hurt that I have a rather nice arcade stick with a rather similar throw and feel to the original hardware, either.
So, I'll just quietly await the day I can load the default ten carts into the PC-10 emulation and see it precisely how I remembered it, and continue using all three methods of playing the games I own.