If contact management is your primary focus I would think that the treo is a better choice. I'm assuming you are using a third party software like ACT or Agendus for advanced contact management. Although new software is coming out for BB all the time, it has not reached the level of maturity of Palm or PPC.
If you mean you just want to have lots of numbers, e-mail addresses for lots of contacts and synch with Outlook, I would think it would be awash.
As far as phone management that is far too subjective for an individual for me to comment. The last treo I had was a 300, but I liked the phone integration better than my PPC phone. I like the buttons for call management that would come up on the touchscreen. With the Blackberry you can almost thumbwheel everything so that is nice. There may be 3rd party s/w for the BB that gives you the quickdial button feature of the treo.
Another alternative for you needs would be a two piece solution with a separate Palm or PPC and utilize bluetooth to autodial your phone o[or BB], etc. Then you would have the benefit of a nice large screen.