Some systems, for whatever reason, simply don't succeed commercially.

Of all the unsuccessful systems in the history of gaming, which one do you think is the best, and what makes it deserving of this honour in your opinion?

SEGA Saturn

SEGA Dreamcast

TurbografX16 (PCE did well in Japan)

PS Vita

Were N64 and XBOX considered successful? also current gen xbox seems like a failure in most people eyes, i would that's the best by far.

N64 and Dreamcast. Both had so many great games and some of the best of the generation but they couldn't complete with the Playstation's . I wouldn't call N64 a failure but Dreamcast was and unsuccessful

PS3

Yes I know it sold a lot, but Sony lost shit tons of money. It's sair to call it a unsuccessful system that make Sony lost their stronghold in console market

Still have a pretty good game library, despite of it poor commercial performance

Hard to say without qualifying "unsuccessful".

The definition of "unsuccessful" is debateable, so it's up to the individual to make a case for their choice.

ps3 lost money  but it did not destroy the playstation brand which is way more important, as we see from how succesful ps4 was. it woud have to be xbox one  imo cause it really killed the brand, and it had the most games ever of any failure of a console.

As defined by:

Sales - Dreamcast
Profit - PS3
Expectations - Vita
Market Share - GC
Brand damage - Wii U

The PS Vita, Dreamcast, and the GameCube for me.