MM Vs. TP - Which One?

I suspect this is an oft asked question, but which is better, a Magic Mouse or a Track Pad.

I started out earlier headed to the local Apple Store to buy a track pad because I wanted the same capibilities on my Mini as I have on my MacBook, but after reading for a few minutes I now wonder if the TP will actually do everything that a Magic Mouse will do.

Can I click/double-click with a TP? Can I navigate screens and menus with a TP? Will a TP replace my mouse(I have regular BT mouse now)?

I have a disability that creates hand problems so I really need to understand before I head to Apple and reading through the reviews in the store I am seeing a few comments that make this a bit more complicated han I expected.

Thank you very much...