The two determining factors for me are user-changeable batteries, and constant-on switch.
I know myself, and know that if I had to send my little flashlight back to the factory to get the batteries changed, it would basically sit on a desktop with a (bring to post office) note on it, until the day my daughter knocks it behind the desk and it's lost for years. For me, not having user-changeable batteries makes it useless.
The other thing is the constant-on switch. I use it so often, that it's easily worth a few extra dollars to me.
I know plenty of people who disagree on both those points, but those are the decision points I'd use.
Joe