Is there any conclusions on whether SEs prefer to see <b>Keyword</b> or <span style="font-weight: bold">Keyword</span>. Ditto for italics. Blogger's rich text editor puts in the spans, but lately I've been swapping them out for <b>s and <i>s where I want to use them.
No, in the sense that they are still part of the HTML standard. However, hardcoding visual formatting into HTML is depricated and useing css to format/display your data is currently recommended (and a lot easier to change if you want to modify later). However if you use css directly in the the tag instead of css classes, you lose that benefit. But hey, it's your site, do what you want (I still use <b> and <i> tags btw)