BC:
Like other series, there are dry moments (sidestories of non-primary character) that may have been value-adders, but digressed from the main storyline too much for me (ie: one of the last few issues regarding the supermodel and her new career).
However, once you get to the last 100-150 pages of the series it becomes a race to the end (it was the last 300 pages for me). The last issue was good, but I have mixed feelings on how it ended. If we were all sitting in a round table I'm sure there could be some interesting philosophical discussions around "what does it all mean" in the Y universe. I'm still trying to process it all and understand what BKV was really trying to express with the series.
(1) Does gender matter?
(2) What is the author saying about love?
(3) Is fear what motivates people?
and on, and on, and on....
I would like to see a companion book for readers after the story that discusses some of these topics, but I don't think it would be very popular. Most just want to read something. I like to understand what I'm reading.
In the end though, I highly recommend this series, which can be a surface story that can be much deeper if the reader chooses it to be.