Just had a look and yeah, the IDJ2 is quite a lot improved from the first one. Only need one ipod and it now has looping funtion, which is sweet. Definitely better than the first model.

As for Numark, they aren't the best quality, and my mixer is quite plasticy, but at the same time I've had it for about 2 years, and it has taken a battering at after parties etc etc, and still works. One play button sticks a bit now, but it's lasted well considering it hasn't been wrapped in cotton wool.