I started with gaiters because I wanted to keep the rain out of my boots. That was until I realized that there's nothing that you can do to actually keep your feet dry. At that time, I was wearing goretex boots and had goretex gaiters. After several hundered miles, the goretex began to wear out in the boots and my feet began to get wet. Even days after it rained my feet were still wet because of those damn heavy leather boots. So I switched to running shoes and packcloth gaiters. No it doesn't keep the rain out (but neither did the other combo long term), but it does keep out pebbles, twigs, dirt, etc...and the entire combo will dry completely in the sun in just a couple of hours.
It's not about keeping your feet dry during the rain...it's about drying them out quickly after it stops raining.
-Howie