In your opion what type of phone is best? The Treo 750 or the Samsung Blackjack?

I am deciding between the Samsung Blackjack and the Treo 750. Which one is best? I do a lot of AIM, MSN and I like to use my phone to balance my checkbook and get directions. Your opinion is especially helpful if you've had both types of phones but I'll take everyones input. THANKS!