Forget Cowboys Vs. Aliens, this is Cowboys Vs. Zombies and it's much more fun.
It had a bit of everything I like in a book: romance, adventure, cowboys...and I kinda like zombie books, too (though they have to have a bit of romance in them as well). It didn't shirk on the horror details either with some rather creepy scenes involving one family.
I really liked Trace/Cowboy and Elisabeth/Red. They were both really great characters and I have to say that Cowboy seemed like the ideal guy to meet in a wild west zombie apocalypse. As for Red, she was pretty kick-arse. The secondary characters were cool too.
I'm very intrigued as to what will happen next in the series and can't wait to read the second book in the series.