Read reviews. Lots of them. And think about the conditions you will use it in. I saw lots of reviews of units that said they didn't work well under clear blue skys. DAFQ? Thats like a bunch of my shooting time. Others that didn't work well under cloudy days. Dafq part 2?

I still haven't bought one, because I'm just not sure that sub $200 range Chrono's are worth it. But I'd love to have my mind changed.