It's the one biography of Shakespeare to read if you're reading only one! I like the way that he rips into the discreditors. I can never understand how someone can devote one's life to discrediting the work of someone else.
I have enjoyed all of his books except:
I found most of "Seeing Further" impossible to read. Too detailed and technical. Bryson is the editor (and bandied about as the author to the outsider), but he didn't exert much influence.
I also found "Bill Bryson's African Diary" disappointing.
I loved his Notes from a Small Island (as far as I know I've read all of his books). You get the impression that he would be a real interesting guy to travel with -- I would have loved to tour Australia with him
Bryson is, of course, first and foremost a scholar of English, and Shakespeare in all his spellings is one of his areas of expertise.
I strongly recomend his "Mother Tongue" to put in context the differences between British and American English.
I'll always admire Bill for his chapter on Liverpool in "Notes from a small island", he completely 'got' the place (where I grew up).