Useing text or alt tag is ok. as a text is visisble and alt tag is not, one tends to believe that search engines will like it better.

But dont hide text, a lot of users use text-indent: -99999px to move text off the screen. This is a signal of spam to google.

Good answer.

If i were a search engine, and some one searched for a blue widget, i could return a page that mentions a blue widget and has an image, that maybe of a blue widget. Or i could return your page that has a image marked up with HTML5, and microdata telling me that the image is in fact of a blue widget along with all the other details you can mark up with microdata and html5 telling me that the page has a lot of information about blue widgets, i know whitch one i would return to the user.

I agree they are equal in SEO, but I also agree you will get differing opinion about looking spammy. i think hythens look spammy, but are coming a bit more normalized as time goes on, but anouther reason is that they are hard to say, image a radio ad, the reader having to explained the hythens

at coca hythen cola dot com

Depending on how much link juice a page has, really rules how many links it can have.

link juice of a page is split between its links. Each link passes 85% of its link juice, this is so link juice does not flow for ever and stops eternal loops
but even losing 15% link juice as link juice passes though links it will never reach 0, as there with always be 85% left, so at some stage link juice becomes too small to pass on and is discarded.

so to get back to my point, if you have too many links it may be that you have split link juice so small that it is discarded and not passed.

Also it would seem that Bing will only index so many links

http://thatsit.com.au/seo/reports/violation/the-page-contains-too-many-hyperlinks

So usability is really secondary