Best console not from Nintendo/Sony/MS/Sega, and why

[Leynos]

PC Engine/TurboGrax-16.

It has a fantastic library of Platformers. RPGs like Ys and Cosmic Fantasy and Far East of Eden to having the largest shmup library of any console of the era. Literally over 100 Shmups. It had some good arcade ports. Created Bonk and stuff like Legendary Ax and the best version of Castlevania Rondo of Blood.