I installed a Stanley steel door in 2000, and it just so-so. The rubber sweep weatherstripping at the bottom starting falling apart the first year. The steel is very thin and prone to denting. If you have kids, it won't look good for long.
Consumer Reports had an issue on doors a few months back. They liked the fiberglass, but noted that they were more expensive.
Home Depot carries "Feather River" doors, which look nice and come in your desired finish.