I don't know, I suppose I consider both Nintendo and Sony to be of top caliber when it comes to gaming. Both companies have made some blunders over the years, but when considering their overall quality of products... it is a tough choice which is better. Looking back I would say Nintendo, looking forward probably Sony.
My favorite home consoles per generation are NES, SNES, PSX, N64, NGC, PS3 and for handheld consoles it has traditionally been nintendo's offerings, though i guess i do usually prefer the PSP over the DS, so Sony may have me with the NGP over the 3DS, though I will still get both.
From a software perspective, Nintendo's first and second party quality is certainly the best, but the majority of the good third party games (and therefore most games) over the years seem to be exclusive to Sony's platforms. My only gripe, about the Sony platform games, is about load times. I am really hoping they alleviate this in the NGP, since it is Sony's first attempt at a non-optical media.
Also, I do consider Nintendo bringing motion controls and touch screens novel ideas, but it seems to be taking gaming in a direction that I am not interested in as a consumer. IMO, the best Wii games do not use any motion controls and the best DS games do not use the touch screen. I am willing to give new ideas a try, but if the idea doesn't enhance gaming then it is unnecessary.
It will be interesting to see if the NGP's back touch panel is used any better by developers. Essentially, the back touch panel may be the first try to expand controls since the shoulder button, if you think about it, most controller changes have been enhancements like the d-pad and analog sticks, or attempts at replacement, such as motion controls and touch screens (since they are usually not used simultaneously with buttons and tend to interrupt game play flow). Hopefully, developers will be able to integrate the back touch panel as fluidly into game play flow as the shoulder buttons were. And, though I am getting a 3DS, it is only for the exclusive content; I will not be using the stereo 3D and will be very disappointed if developers are heavy on the gyroscope, accelerometers, and touch screen usage.
On a side note, I would put Sega at a solid third and Microsoft...fourth? Honestly, from all the software and hardware Microsoft has produced their only first rate product has been windows 7; that is not saying much considering how many products they have made.