Vertigo is really done a great job of actually being a separate line of books from the DCU. Marvel has tried for years to have a separate line of books and has yet to have a line of books that are not part of the Marvel Universe really stick. Kudos to Marvel for continuing to try as any differential of comic lines is a good thing. This is just my quick comments on the Vertigo books that I read.
Fables - Hands down the best Vertigo book and one of the best monthly series in comics. Month in and month out these are great stories that you want to read again and again. Not only that but Willingham moved away from what appeared to be the main characters of the book and never lost my interest. Thankfully Bigby and Snow White still show up from time to time.
Other Side - A mini-series about the Viet Nam war, with the perspective of soldiers from either side coming into the war and what appears to be their inevitable meeting. I've enjoyed the first two issues, but as I was never a solider myself I can't gage if they are getting the war part right or not.
Exterminators - A very good series that is about the life of the people who are exterminators and the bizarre super bug they have created. Well written and well drawn.
Deadman - A really neat series about parallel universes, remote viewing, what is death and many other themes. I have a feeling it won't last long because using the Deadman title was a mistake, because people would want the old DCU character in the book and not this character. Still I'm enjoying it while it lasts.
Hellblazer - On issue #227, this series just goes on and on. The current writer is doing a great job on this story arc about the Empathy Machine. John is this asshole sort of magician, who has pissed off everyone in his life, yet you still want to root for him. A true anti-hero in the best sense of the word.
Testament - A good read, but I think I would get it more if I read it in trade. Still a wild ride juxtaposing a biblical and a modern day story.
American Virgin - This series continues to defy my being able to peg where we are going next with this book. The lead character is being challenged to maintain his beliefs in a harsh and at times sick world.
Jack of Fables - A Fables spin off, which is fun so far. I wonder if a dislikable character can carry a series for a long time, but Hellblazer proves that it can be done. A nice spin off, that is still remaining true to the Fables theme.
Loveless - A very different western written by Azzarello. I know it reads better in a trade, but just the overall feeling this book generates is amazing. I love this book and can't really tell you why all the time, although shooting the main character in the book and either killing him or sidelining him for awhile was a shocker.
Vertigo has been a great line and produced Sandman, Doom Patrol, Human Target and other great series over the years.