I've had the same set of Frogg Toggs for four years now and still no leaks.
A lot of my LD riding is out west where wind and chill can be an issue even in the summer, and I've used my FTs about as many times as a wind suit or even as pajamas in the night chill when camping as I have worn them in the rain. One of the the things I like about them is they breathe, instead of making you feel like you're wearing a big trash bag. It doesn't do much good to put on rain gear to keep dry if you sweat so much under it that you're soaked anyway.
Like others have mentioned on here, I also got mine big enough so it fits easily over my riding gear. Sure, I feel a bit like the Michelin Man when I'm wearing it, but when it comes to keeping dry, warm, or otherwise comfy, style considerations go out the window.