It's fun, it's silly, and it's simple.  Robot is the big introduction of the Fourth Doctor and I enjoyed it overall.  Sure, some scenes and moments feel like they kind of waste time more than progress the plot.  But it's interesting.  As our first step towards a new era, it still feels like a transition out of the UNIT era.  This could have been a Third Doctor story very easily, but that's not a bad thing.  It blunts the blow of the regeneration a little bit and allows for a transition into the new doctor rather seamlessly.

Tom Baker shows how fun he can be pretty quickly - that Robot clip almost immediately proved he was going to be a unique and unforgettable force in this show's history.  The UNIT characters and Harry Sullivan were all pretty charming, too.  I got a lot of closure out of the Robot episodes because of this, even with all the cheesy effects around K1.  The robot was fun more than anything.  I really like his rampage at the end even if it didn't look great.  Overall it's a very cozy experience I quite enjoyed, with all its flaws.