Depends on what sort of beer you're looking at. That being said, according to the specs, Poland Springs runs relatively soft, making it a good (IMHO) candidate for lighter beers. Wish we could get it in this area. Last Pilsner I brewed I used Ice Mountain cut with distilled.
I use Poland Springs to brew, its the only water I really like the taste of. I figure start with water you like. Good water=good beer(well the start of good beer).