man I love the stories where the Doctor meets his past selves. I wish Tom Baker would do one of these while he's still with us. there just haven't been enough of the "original" Doctors meeting the newer ones. just for fun's sake.
this one works really well since it's so short. and it's got a really nice ending. plus it's just the two Doctors playing off each other which is a lot of fun as well. they never do like each other at first. nice to see some things don't change.