I did the lip at counter height, 36". Comfortable height and can also be used as a laundry sink. The floor height is just about 11" below the lip.

What are the dimensions of this? Love it!

It's about 40" x 40", 11" deep and 36" high.

And what did you use as the base of the sink? Is it tile or a plastic base?

The whole thing is tile. I had my cabinet maker build the bottom with plywood and it was treated just like a shower pan :)