Granted I did not use or play the original XBOX, I decided to go into my local gamestop to try out the X360 on display, for comparison to the PS2. Granted most of you have read reviews like this, I'm going to post it anyway.
The first thing I noticed about it was the controller. I have to say that it was very akward to use. the d-pad and left analog stick were switched. This is a big red flag. Also, I think this was the case as well with the XBOX, but the buttons were primarily color coded on the controller, while they were primarily letter coded on screen. Another big no-no. What finally made me decide that the controller sucked was the shoulder buttons. The primary set is a flat style button like the ones on a PS2, and the rear set is a trigger-like style, kind of like the Z button on an N64 controller. Made for a very confusing setup. Also, plain white controller FTL.
Now onto the gameplay. I had the benefit of having a miserable 2 playable demos, and 8 trailers. Not really representing of what this console can do. The TV I played it on was a 17.2" widescreen LCD TV. The colors were nice and vibrant, reminded me of the Dreamcast.... But then again, that could have been the LCD talking. The first demo I played was Kameo. The controller problems mentioned above made this game nearly unplayable. The picture quality was not that great, it looked like a third generation PS2 game (think Soul Calibur 2). I spent two minutes before moving on. The other one was either Socom 2, or Splinter Cell 3... Cant remember which one. The eyecandy was outstanding. I was very impressed with the presentation of this game. However, it had that 'You must shoot the enemy 8 times in the head with your magical crosshair' feeling to it. I blame the genre for that, though.
As far as capabilities went, there was absolutely no lag, merged frames, or choppiness. Sound response was immediate, also without problems. I went into the 'dashboard' as some people called it, and it seemed very neat and simple. A little limiting, but I thought it was OK. Gamestop didn't have connection to Live, so I can't comment on that. It genuinely felt like a next-gen console. I was not expecting for it to look and sound this good, but even then, it was still overhyped.
Anyway, I left the store with mixed feelings. I thought the hardware was great, but the control of it was not up to par. I am also not happy with the fact I'll have to wait until February before it becomes commonly available. Hopefully by then they'll have a real controller and capabilities for a custom UI... And there had damn well better be more than two demos...
So if choice came today whether to buy it or not, I couldn't answer.