As a long time Atari fan, I'll speak positively about the big three in general. At least they're not bankrupt.

Microsoft: they offer good competition for Sony which makes it harder for them to monopolize the market.

Nintendo: thank God they're around for all our kids. I was very happy playing Mario in my childhood, if i had a child i'de want him/her to meet this adoreable plummer :)

Sony: has good third party support. They have also released a ton of new first party games this gen. Their hardware is designed great.
Microsoft:has great exclusices, great advertising, with the best online play.

this is hard.... not to mention a slippery slope for betting banned

MS: they conquered the US market and in 2008 with the "Jasper" motherboard they made the Xbox 360 reliable

You fail this challenge i see.

Sony has some really cool first-party IPs.  I am a fan of LittleBigPlanet, inFamous and Uncharted.  I also really like the backstory of the Killzone franchise.

I would add my dislike of Sony comes far more out of gloating internet fanboys who trolled against the likes of Sega, and put a seriously bad taste in my mouth than anything else.  Although the arrogance of the PS3 launch did add something to it.

Ok so maybe I was twitching a bit....

Microsoft knows how to make money.

Sony: Has a lot of great first party games.

Microsoft: Halo looks cool.

MS: Gears of War logo looks cool as hell