My votes go for the Amiga and the PC Engine.
The Amiga was tricky to develop for, particularly if you wanted to use all its custom chips to their full potential. So many Amiga games are just questionable ports of Atari ST or even 8-bit home micro games.
The PC Engine was really ahead of its time, but it's now kind of an obscure little thing, and a bit quaint when put up against the SNES and Mega Drive.
They're actually really nice, well-made X-COM lites. Great if you don't want to immediately throw your kids to the Chryssalids.
Rabbids still kinda suck as a concept, but the games are good enough that I can look past it