Still well worth watching if you ask me. As a three-part episode (of which, Utopia was by far the best) it was overall a brilliant end to what has been without doubt the best series of the three series since the show was revived. Don't get me wrong, this episode did have faults, but on the whole, it was very well done.
First, the gripes. Captain Jack is criminally underused in this episode. After his brief appearance at the start where he gets killed (again), he doesn't say another word until just before the Master's downfall. For probably the best semi-regular character in the show, this was a great shame. Similarly, the femme fatale that was Lucy barely got a look in. Off the top of my head, the only words I can think of her saying are describing when the Master took her to the end of the universe. Obviously she did have an integral part in the plot, but I think she could have said a bit more, rather than spending the episode essentially as the trophy wife. Also, I found the Doctor's eventual "resurrection" was a little hard to get my head around, and there was no possible way that Martha could've worked out exactly what the spend the next year doing just from the three words that the Doctor whispered in her ear.
Now, the pros. As if everyone didn't already know, John Simm has once again shown himself to be an absolute diamond. His performance as the brilliantly psychotic Master is sheer perfection, no actor on the planet could have pulled it off better than him, and his casting was nothing short of inspired. Freema Agyeman's performance is also heroic as she takes centre stage for once, as it's obvious how hardened she's become by the events of "the year that never was". Also, once he gets back to normal, David Tennant comes right back into it as if he'd never been reduced to a 100 year old man in a wheelchair. The revelation behind the Toclafane and the Tardis/Paradox Machine was brilliantly thought out and flawlessly written. And on a lighter note, the use of the Scissor Sisters' "I Can't Decide" when the Master is dancing around on the deck of the Valiant is a Midas touch when you listen to the lyrics, they fit the situation like salt and pepper.
Overall, a good finale to the series. Here's looking forward to Voyage of the Damned at Christmas, and, of course, the already well-publicised guest appearance of Kylie Minogue...