I'm just wondering whether they named it The Trip as a sort of injoke recognition of it being an 'ego trip', as they must know many viewers think of it, as an added tease? There are several other things they could've called it and the writing is very good so I'm going with this theory - so that would make it a self-satire in their eyes, if they wanted to defend it. And practically everything I've seen these two do does have a self mocking tone to it.
Just watched episode 3, it went a bit like this for me Finished with a bang. Generally very good indeed apart from the unbelievable old lady Brydon fan, well the show prides itself on its perfection in all other areas, I thought that was bit was weak, but the pay off at the end, sublime!
Also I'm really struggling to decide which is the better impressionist, for some it's Brydon, others it is Coogan, it's a tough one. My favourite so far, Coogan's James Mason, brilliant, but I wanted to see Brydon try it too.
Have forgiven and forgotten about the obvious self indulgence of it all, it is a little cracker of a 'sitcom'.