If you're the only one using SharePoint from a PDA then you can probably stick with the browser. That said, if there are a few of you using it then I agree with James; you should check out a 3rd party solution if you want mobile access to SharePoint from your BlackBerry.
I can't really speak to your individual case (everyone uses SharePoint for something different) but my company, WICKSoft, makes a mobile SharePoint solution specifically for the BlackBerry. Here is a link to the SharePoint info: Mobile SharePoint on the BlackBerry with WICKSoft
Basically it gives you a 'BlackBerry' experience for everything in SharePoint and is used by people all over the world. Aside from being way faster than the browser, it lets you do a lot of things that are simply not possible from a 'vanilla' BlackBerry.