I complained that it is sometimes difficult to tell Patrick Troughton apart from the other actors on the audio tapes. There is no problem at all when you are watching the programme; he is at the centre of every scene he is in. And this is not just the natural effect of the director concentrating on the central character: Troughton is simply fascinating to look at - such an expressive face.
The story is of course a classic. The Cybermen - or rather, the Cyber-controller, who is the only one who gets significant airtime, with Peter Hawkins' superbly chilling voicing of the lines - are worthy adversaries, assisted by their human dupes (vaguely foreign and therefore sinister, unlike the spaceship captain who is American and therefore clearly a Good Guy). The Cybermats could very nearly have been awful, but carry it off well. There are certain implausibilities in the set-up - why do the Cybermen limit themselves to a single means of egress after they have been woken, with the revitaliser on the other side of the hatch? Why does the Doctor allow the Cyber-controller to recharge himself? - but you can overlook them in the fun of the ride.
There are some nice little touches as well: Victoria's reaction to the Tardis; the Doctor and Victoria about their families; the Doctor telling Klieg just how insane he is; Toberman cradling his dead mistress. I even quite liked the special effects of the Cybermen doing mind-zinging things - would look very silly now but fitted the 1960s feel of the series.
The DVD has a couple of great extras as well: director Morris Barry's brief introduction to the original video release, excerpts from a panel discussion in 1992 which brought together the surviving actors and crew from the series, and slightly to my surprise but much to my delight a very brief video of the Dalek civil war from the end of the previous series, The Evil of the Daleks.
In summary, this is a DVD well worth getting hold of.