There are many valid criticisms about the Chibs era but Power of the Doctor is fucking incredible and nobody will convince me otherwise. If it wasn't for the weird clothes regeneration it'd have the absolute best regeneration hands-down, imo.
'The Power of the Doctor' is the 2nd best regeneration story of the revival ('Parting of the Ways' is, of course, the best).
But "Doctor Whoever-I'm-About-To-Be....Tag, you're it!" is such an all-timer final line. Brilliant closing moment, ironically changed during the edit.