Water-Based
Water-Based or Oil-Based Polyurethane?
Oil-Based
The National Wood Flooring Association offers a great side-by-side look at a variety of wood species with both water-based and oil-based finishes. You can see some examples here: NWFA's Species Gallery.
Choosing The Right Finish
Below is a comparison of Water-Based and Oil Based Polyurethanes. There are a lot of facets of each finish, and plenty of options to go with them!
Do you have more questions? Are you ready for an estimate?