What can I say, I've been a Whosian for several decades and the Dr. can do no wrong, no matter in which regeneration; I enjoy watching and rewatching episodes. This may be why I see no discontinuities, I'm "intimate" with the story lines and characters. FYI: apparently the last disc in all the series is the documentary disc.
Watch the Bonus Material!! It explains all this better!! Okay, now... Although presented as a 12-part story, it is actually two separate stories connected at the end and beginning, nothing more. Being two stories, this will be hard to review with the pathetic character limit. Frontier in Space lacks a proper conclusion, but you do get the impression the two sides will smooth things out. Planet of the Daleks is actually a rehash of the original Dalek storyline with updated elements and new characters, but it ends on a high note and wraps up the overall storyline. Both stories are very watchable and the actors pull off their roles perfectly. The miniatures used for Frontier look good for the time, the Draconians are well designed, and we again see the Doctor facing off against the Master. The concept of invisible beings in Planet is well executed with a then-brand new technology and we learn more about the Daleks. If only they could have tied the two together more seamlessly.