The Sierra Designs stuff is fairly cheap, easily packable, and moderately durable. If you want really good stuff pick up the Helly Hansen work wear. I've got a set of both, they each serve different purposes, but if I'm going to be working outside in a monsoon, I'm in the Helly's with a set of Neos. Rain wear shouldn't wear out if you use it every day.
Frogg Toggs are about the cheapest thing on the planet. I bought 2 sets. The first shredded my first day at work. I thought maybe it was a fluke so I bought a second set. Those shredded the first day I used them as well. They suck for anything other than a quick set if you need to stay dry for a short time, not for constant wear. Keep a set in the car for changing a tire in a downpour, don't buy a set thinking you're going to take them through the woods.