Remember that one scene in The Office where Jim gives Pam a tea-pot with surprise gifts inside? Think of this PDF compressor as that tea-pot, because there's so much more you can do here.
For starters, you can drag and drop on ILovePDF (yay) or even link your Google Drive/ Box folders. Once you do, it's as simple as choosing what type of compression you want (the "Recommended" option is usually the best bang for your buck), and waiting for it to compress.
Obviously, the heavier your PDF, the longer this might take. But for reference, I uploaded a PDF sized at 38.19MB, and downloaded a similar quality one at 18.74MB (that's 51% smaller).
Here's where the 'surprise gifts' come in. ILovePDF lets you automatically add page numbers (literally on a specific position, if you so choose), rotate PDFs, add passwords to protect them, merge other PDFs or even split them up.
Plus, if you go to ILovePDF's website, there's a world of other features they have. From converting PDF -> Word, JPG -> PDF, adding watermarks, editing PDFs... you read that right. I said editing PDFs. You truly start loving PDFs.