Below you can discover the pros and cons of using water based polyurethane, as well as oil based, and some basic information on both of these products.
1. Drying Time
Water based polyurethane requires little time to dry. This allows you to start your project in the morning, apply all four coats, and still be able to occupy the room that night.
Oil based polyurethane does require less coats, but also requires longer drying time between coats, as well as a large amount of drying time after the last coat is applied. This makes it pretty much impossible for the project room to be utilized until the following day.
2. Finished Affect
Water based polyurethane leaves a clear coat on the surface you are covering. In fact, it is so clear, that sometimes you are unable to tell exactly where your brush line is. In the can it appears creamy, however, when applied, it becomes clear. Therefore, you get the actual wood color showing through, and only that.
Oil based polyurethane leaves a glow or shine in an amber color to the finished surface. The finish still possess the look of your wood, but with an added extra.
Depending on what you like best is what you will want to purchase. Whether or not the sheen is present, gives no dwelling on the quality of your surface, or the things your surface will withstand.
3. Working Environment
When looking at health and safety considerations, water based pulls a little ahead of its competition. Water based polyurethane has a very low odor, and because of it's quick drying time the odor is quickly gone.
Oil Based, on the other hand possess a strong odor, that may become hard to handle after a bit of working with it. Also, because of its prolonged drying time, the odor tends to stay in the room longer than you may want it to.
When working with water based polyurethane it is pretty easy to do any touch ups that are necessary. The finish is light and is easy to change, or add something that was missing.
Oil-based polyurethane is harder to do touch ups, because of the thickness of the finish. If touch ups are needed make sure you deal with them right away before it dries.
Water based costs a bit more than oil based polyurethane. Although oil based polyurethane seems to contain more in it, when it comes to cost water based is the one that will eat up more of your home improvement money.
When you finally decide to make your journey to the store, remember that the decision should be based on what you are most comfortable with, and what most meets your needs. Good luck!