In my opinion, not a great episode and a poor way to close off an era I already wasn't keen on anyway. The Water of Mars, which was a brilliant episode, set up something amazing with the "Time Lord victorious" theme yet it was followed up by Ten being a bit too mopey and self-obsessed, acting completely uncharasteristic and even unlikable. The Master, too, was really poorly presented, coming off to me as a parody of the Joker but with superpowers for some reason (still don't understand why that was neccessary). Others gripes include the cheap revelation of how Donna survived her memories returning, and uninteresting cardboard-cutouts for side characters.
The worst part for me, however, was how the whole regeneration was handled. Yes, it's supposed to be sad saying goodbye to a Doctor, but at the same looking forward to the future of the show instead of treating it like the very end and making people hate the following Doctor before he'd even been on screen. It really didn't need to be dragged on so long, either.
I did, of course, really enjoy Bernard Cribbins as Wilf, who is one of the coolest characters ever, and I thought Timothy Dalton as Rassilon was fantastic. Definitely somebody who should return to the role.