Well, I think a few minor typos here and there are not that big of a deal. I sure make a lot of typos. So I'd say mostly content. Everyone makes the occasional mistake. Even in this day and age of spell/grammar check, mistakes do slip by. What you showed us from that press release would not make me not want to buy the book and I'd be much more forgiving if a press release was poorly written than an actual book.
However, if a book itself is written with numerous, major errors, then I'd probably either not buy it if the mistakes were distracting and consider alerting the publisher (who may not even be aware...I work for a publisher...trust me, it happens) and ask them for a refund.