Whatever engine Apple is using to view PDFs in Preview, it doesn't always display PDFs correctly.
It's much faster than the bloated beast that is Acrobat, but I'd say about 20% of the documents I open in Preview have to be viewed in Acrobat to be usable, so I've just defaulted to avoiding Preview instead.
A good, fast PDF viewer in the browser would be far better than either of those options.
What kinds of PDFs are you opening? I find the failure rate in Preview is more like 0.5%, and it's generally related to annoying (Adobe proprietary?) form-related stuff.
Plus Preview can also do some very handy basic editing (cropping, adding/deleting/reordering pages, etc.), which I can only assume Adobe have left out to in order to up-sell you Acrobat.
It's much faster than the bloated beast that is Acrobat, but I'd say about 20% of the documents I open in Preview have to be viewed in Acrobat to be usable, so I've just defaulted to avoiding Preview instead.
A good, fast PDF viewer in the browser would be far better than either of those options.