When looking for a shoe, I like one that has good lateral support. The lightest shoes tend to be nothing but mesh uppers, and that's nice for cooler feet. But with only mesh to support you, you may find your feet squirming around in your shoe or that you are contorting your feet to not slid one way or the other in your shoe. The picture below is of a Salomon XA Comp 6 (13 oz - Size 9). I don't have this shoe but I do have the XA5,which I really like. It is good in the Sierra and on what ever trail you use it on. Anyway, notice the nice lateral support, plus good cladding around the lower mesh material so it is not as likely to get sliced or torn. Remember, the photo is just for example. I'm not endorsing any shoe here.
As has been said by several in this thread, fit, fit, fit. Next and nearly important is some lateral support and most likely you'd like a good rock plate as well. All worthy considerations. Good luck in your journey and decision making. Just remember that if you don't like your first pair, go find another pair and just have fun.