I can’t remember the precise differences between them but I think you’ll be able to do all you need to do with the free Adobe Reader.
You only need Acrobat Pro if you’re creating PDFs for publication and need advanced editing, colour management etc. One of the main reasons I need Pro at work is tagging documents for accessibility, which you can’t do with Reader.
As Roger says, if you don’t need all those advanced features, there are probably better alternatives. I would prefer not to install Adobe products on my computer if I had the option to use something else instead.