The combination of Blackberry and BES is the correct choice if you want a secure enterprise solution. With a BES server you have complete control over the phones. Policies allow logging of everything that the phone does, including if you want all incoming and outgoing text messages, push and pull apps and calling restrictions.
The difference between consumer and enterprise blackberry is that the BES server has a secure key that you create and is unknown to blackberry, bis is controlled by blackberry and is snoopable by governments.
I've found that the battery life is better on a blackberry, but the browser isnt the greatest, but has improved in the newest models. Another thing to keep in mind is the battery is field swappable, so if the battery wears out, YOU can switch it out, or carry a spare.
Blackberry made the mistake of getting into consumer phones, but for enterprise situations, blackberry is the best way to go.