I have to admit. The one thing I do not like about Nick's ownership of the Turtles? There's no 2k3 references anywhere. They haven't made plans to release any of the 2k3 series on DVD (other than the bare bones release of the telefilm, not even the extended 4Kids website version), and all the non-Nick Turtle merchandise is the 1980's series. Which isn't bad, exactly, but it would be nice to give a nod to the series in between the oldest and newest one.
But I really am disappointed that there haven't bothered releasing any of the 2K3 series. I really had hoped Nick would allow Shout to release it. Most of the series except for Back to the Sewers was released on DVD, but mostly single disks. Half of season 4, both seasons of Fast Forward, and the first 2 seasons have been released (in half sets, and Season 2 part 2 is apparently impossible to find). 4Kids stopped releasing DVD's well before the Nick sale (no thanks to a tiff with Funimation, the distributors), and with the entire line long out of print, it's impossible to get any of the series now.
Unlike the original 80's cartoon (now completely released), Nick actually has the rights to 2k3 (Fred Wolf and Lionsgate still own the show rights and home entertainment rights respectively). Oh, and the live action series is only available due to Saban. Forgot to throw that in there.