So, the elephant in the room: This is the Doctor Who episode with Jimmy Saville in it. As such watching it proves to be very awkward indeed. However it should be noted that despite Jim's less-than-noble actions on many occasions this was apparently not one of those times according to Gareth Jenkins. So there is that.
Because once you get past the evil man hosting it (and casually joining the cast to break the fourth wall at the end) you'll find that this actually forms an interesting time capsule of sorts for the state of Doctor Who at this time: violent and an initially-offputting Doctor. Take for example the final defeat of the Sontarans or the bickering between ol' Sixie and Tegan.
This is certainly one that Doctor Who fans should see. It demonstrates the state of the show at the time perfectly and we get to see the man behind the Sixth Doctor for what he really is. Colin Baker is the single nicest and friendliest person ever to be in Doctor Who and that's exactly what true Whovians know to be the case, haters be damned, and Gareth Jenkins will always be our champion who knows this firsthand.
For how wonderful the good people at Doctor Who were to let Gareth be in his favourite show I believe this to be worthy of a full ***** despite the aforementioned paedophilic elephant in the room.