I enjoyed After and Again. It was reminiscent of a western but with just enough hints of a vanished world to take it away from John Wayne territory.
Zack is reasonably well written, he's not a superman and his reactions mirror that about himself. He has a very sweet relationship with his wannabee girlfriend and comes across as very sincere in all of his dealings.
The secondary characters are well drawn and understandable and I enjoyed reading about them. There wasn't a point where I rolled my eyes and put the book down for later.
With all that said however, this book does have some problems.
Trask ludicrously survives numerous life threatening happenings (far too many to be believable) He's also single minded when it comes to kidnapping the designated chick (Zack's girl) for no real reason beyond, the Man says so. It seemed strange that he had to have 'that girl' when it would have been easier to find one from somewhere else.
Too much info-dump, the main character doesn't figure anything out, he gets told everything.
The 'paradise world' came from the left field and really derailed the last quarter of the book. No problem with time travel, really had an issue with other reality because it really had no impact. The plot would have been served a lot better without the Man
But despite the above, it's a well written, enjoyable piece of prose.