I would easily say the Sega Genesis, but since that's the most obvious one that people are going to pick, I would say the PC Engine/Turbographx16 was the most similar console.
A lot of people have chosen the Lynx I see, eh? That console's a complete mystery to me, but if it's anything like the Jaguar, I'm sadly going to have to assume it's a piece of s**t. Sorry lads.
But the Jaguar-review doesn't lie:
Truly an awful, awful console. A rushed-out piece of garbage that is simply mind-boggling. How on Earth could Atari fall so hard from grace?