My main takeaway is that it sounds like a professional production and Colin Baker's excellent performance instantly stands out in this format... other than that I haven't got that much positive to say. It is a tedious story limited by the fact that its been chopped into four pieces to give each Doctor his own episode, then a reunion at the end. It doesn't help that the villain has very little charisma.

It is totally understandable that Big Finish would want to start with a bang though and have all of their stars in one place. I'm sure it helped sell themselves as a legitimate source of Doctor Who back in 1999. I would be interested to hear what listeners at the time thought.