I don't think I had seen a single minute of this story before, and boy had I missed out. It is simply superb, the best story of the Davison era. Perhaps my appreciation was enhanced by watching it immediately after my operation this morning and needing to be cheered up, but I loved every moment: the creepiness of Striker's crew, the glorious Lynda Baron as Captain Wrack, the Marriner/Tegan flirtation, the conclusion of the Turlough / Black Guardian storyline, the choice of Enlightenment itself at the end. Granted, the premise of the story is very silly indeed, but I felt that everyone involved carried it off very well. I even felt that Leee John's performance was peculiar rather than poor. Perhaps that says something about my state of mind this morning.
Frontios is fairly standard stuff; I think destroying the Tardis at the end of the first episode is a bit of a mistake because we know that they must get it back in the end; the Doctor's concern that the Time Lords might spot him interfering seems a bit belated; as usual for this era, the Tardis gets used as an interplanetary taxi; while the speaking parts among the guest cast are generally good, the direction of the crowd scenes is pretty lousy; the blokes dressed up in rubber monster suits look like blokes dressed in rubber monster suits (as in most Davison stories); but there is a decent sf story in there, and if you consider it against some of the competition it isn't so bad.
In summary, a decent conclusion to my Fifth Doctor viewing. I will reserve my overall judgement of the Davison era until I have got through the novelisations.