I tried neoprene over boots. I found that they don't work for me. They are a hell of a time to slip over the shoes, and then they also have to have a hole for the clip-ins. When it pours out, and it does often here, the splashback has a way of seeping in.

However, what I found works great is gore tex socks. The shoes, can get wet all they want, but the feet stay dry.

ya still have to put normal socks on though...