I choose based on the characters.
If she is 21 and the most beautiful woman ever created, flawless perfection and he will die for her—for her looks—because at that point she might have the personality of a cabbage but who cares she looks so revising—you just lost me.

If he is a six-pack-hunk she would swoon for with magic powers that emerge at midnight...I'm out of there.  Not because that is bad, it just isn't me.

I just wrote a preface for my own series in it I describe characters. These are also the characters I want to read about in other people's books. This is the most important thing I do look for when choosing a work to critique.

"There is a reason why the heroes in my novel, as the hero in my own life, my husband Reg, are not the six-pack-chest macho, alpha males as written into many romance novels. My hero’s strengths lie deeper. They know that kindness isn’t weakness and killer instinct and action is not necessarily strength.
I like to think my experiences give me the insight to write salt-of-the earth heroes, and villains who do not come complete with a black heart, for they too are human and love and are loved by someone."

That's it; I'm looking to read about people with interesting lives who I can connect with.