Acrobat Reader is complicated and no fun to use. Here's how you can set Apple's clean and elegant Preview app as the default app for PDFs.
How to Open PDFs on a Mac with Preview instead of Acrobat Reader
How to Compress a PDF on a Mac, Including in Lion
You can compress PDFs using Preview on the Mac. Do it when you create a PDF or do it later on. You can control the amount of compression too.