I have a set of Frogg Toggs, and I am happy with them. I keep them with me and use them in the rain, and as an extra outer layer when it gets cold. They aren't thick, but the fact that they aren't that breathable means they block the wind, which helps when I'm wearing jeans.
I did ride in a soaker of a thunderstorm for a couple hours between Erie and Cleveland. I stayed dry, except for my hands and my feet (the areas the suit didn't cover).
My complaints? They are loose, which means they flap a lot, so I have to go slower. But if it's raining or cold, going slower is recommended, so I don't mind. They have not yet shreaded on me, and I have had them over 3 years. My other complaint is the elasticized pant cuffs. Once they pull up over your boots, there is no way to get them down again without getting off the bike. Then rain starts pouring into your footwear. I could have sworn that my boot were actually filling with water, but it was just that my socks were saturated. Luckily, it was July, and I didn't mind.