Nintendo
Like: Has the greatest franchises out there. Focus a lot on gameplay, longevity and value.
Dislike: Forgets some of their greatest franchises.
Sony
Like: Their consoles always have a very nice and sleek design.
Dislike: Their horrible controllers.
Microsoft
Like: Their excellent controllers, Halo and Rare's IP's.
Dislike: Their heavily unreliable hardware (my current 360 has frozen a few times, and my first one got the "red ring of death"), their mistreatment of Rare and their paid online.