I too came from the PalmOS world, but when the X5 was released by Dell. Now PIM functions were (and are) so integral to my life that functioning without was difficult and stressful. It was tough to get used to PPC PIM use, but over time between Outlook from Office XP and my PPC, I can now say with certainty that I could not go back. When I use my wife's m515 or one of my daughter's m130s, I am lost. It looks as difficult to use now as the PPC platform did to me then.
I now have a 4155 and am loving it.
The short version of this story is you will probably get used to it and it will become natural over time.
BTW: I have tried some add ons and to me they just made the PIM functions more difficult. However, some users like them.
Welcome to the PPC world.
-JmE-