Dark Matter

I think this is like 3.5 stars. I read it over 2 days, and it was a page turner. I went in knowing pretty much nothing about the story. It certainly was a fast read, gripping, with a sympathetic narrator... but any one familiar with science fiction probably guessed where the story was going in the first few chapters. Mild spoilers first, then heavier ones, but in case you want to go in completely cold, I'll flag them...

This isn't much of spoiler, but gives away the genre:
So, the book concerns parallel universes/ alternate timelines / encountering yourself from another reality where you made different choices. In that sense it's derivative from countless sci-fi stories, Star Trek episodes, stories, the TV show "Sliders" etc. Despite that, I wanted to keep reading, and much like those other works, it does make one wonder about one's own choices, and the choices of those around us, and what might have been, what could have been, etc.

Ok, now for real spoilers so don't read these unless you finished the book:

The end doesn't quite logically hold up... if there were 20+ Jasons, there'd be infinite Jasons. I guess more would come through eventually, and they'd never stop. Jason2 should also have had multiple doplegangers trying to steal Jason's life. Obviously, I guess that's necessary for the story to make sense but ... just to nitpick. Also, radiation poisoning and/or disease form some of the other worlds all the Jasons visited? Seems like it'd be an issue...But, they all have an equal claim, the narrator isn't the "true" Jason, just the luckiest one. Anyway, my nitpicks aside, certainly a thought-provoking page-turner, if a variation on a standard sci-fi trope.