The disadvantage to water base urethane is that it doesn't level well, but when you're basically sanding it all off during the grain filling process that matters little. At the end of the process you can go with a French rub if you want to, but what I do if I don't want to invest that much time and work is to allow the final coat to cure for two days and then give it a couple of coats of sprayed on oil base urethane or lacquer.

The other caveat with water base urethane is that it can have problems adhering when used over oil stains, so make sure you use an anilyne dye for grain highlighting.