Terrible.
I watched the Ashes to Ashes finale on Friday, and it did what Lost tried to do and was successful on every level where Lost wasn't.
If you look at A2A, the series introduced a limited number of elements - most of them this series except for the time travel, brought them up repeatedly to remind the viewer of them, and pretty clearly (for the most part) explained what they were and why there were there.
This is structured, well thought out writing.
Lost threw the kitchen sink in, introduced elements that they had no idea what they meant or how they would be solved, left a bunch hanging and introduced elements in the last ten minutes that had nothing to do with the rest of the show that had been built up so far.
It was piss-poor, ill thought out writing.
I wasn't happy with the evangelical nature of either, but A2A at least seems to have had a semblance of a plan that actually was thought out before hand and made sense.
The only finale I can think of that was worse, was BSG's.
This is take from another forum I read...
"The finale didn't answer (or even hint at an answer) to a single question about the island, its origins, its function, the "light", Jacob, Jacob's mother, Jacob's magic powers, etc, etc. The only mystery it did resolve definitively was the "what the heck is this alternate reality" question - something that was only introduced this season.
In other words, instead of addressing the central mysteries that have driven the show since the beginning, the writers conjured up a brand new mystery at the beginning of this season, and then used the *series* finale to resolve only that new mystery. And the resolution to that mystery - that this group had such fun times on the island that they decided to share a slice of afterlife together - is utterly unconnected to any other mystery that has ever been raised in the show. How anyone could watch this and conclude the writers totally had this planned out from the start is beyond me - there's nothing in the finale that would support that interpretation.
Seriously, if you think about it, this "they had such fun together they decided to meet up again after they all died" device could be used as a feel-good tear-jerker ending to *any* ensemble show. It's really a totally meaningless cop-out ending."