Agendus or E-Mobile Planner? I actually have all three but at the end of the day PI stays on my device. Agendus is not too bad just a little bulky to me.
E-Mobile Today Professional is (in my opinion) better than Pocket Informant. I tried Pocket Informant, but E-Mobile Today Pro looks better and is just a simpler and much improved app for my needs.
Agendus is way to slow for my 8900. It takes about 15 seconds to load my task list. I haven't tried e-mobile planer since they have no demo. I did try PI for a while, but ultimately left due to the separate databases and manual outlook sync. With BES, I don't want to every plugin my BB to sync. I do understand why they went the direction they did.
I do use (and recommend) PocketDay Personal. It may not be the prettiest one, but it's lighting fast compared to the others. It's not a replacement PIM like PI, but does provide a good view to your existing data. They have a free demo that you can get to try it out. I found I had to spend some time customizing the fonts, colors, options before I really began to like it.