Jan 2019 UPDATE:
Yumprint has been down AGAIN for about a couple of months. This is not the first time this has happened. Clearly they are not interested in maintaining the website, making this plugin worthless. Because of their lack of attention to keep it up and running, I give this plug 0 stars now.
PREVIOUS REVIEW when things were working:
Mostly I like this plugin but they are a few problems:
1) The save doesn't work and just opens up a blank box with no reason for it not working.
2) It is incompatible with AMP so any site using it will not be able to get AMP SEO advantages for phone queries in Google.
3) Others claim they don't like their recipes going on the Yumprint site. I don't mind that at all. It can give my client a lot of exposure on the Yumprint site, if people can find it there, that is. I can't. So while it may be stored there in their database, I'm not sure they make it visible unless you purposely post it there. I'd love to know if I'm wrong though.
4) It helps SEO. My client is #1 for many recipes and the same recipe on Yumprint's site is nowhere to be found in search. In another search for a recipe, another Yumprint client was #1.
I lived with #1 for a long time. I can't live with #2 though as SEO rank is everything for my client using this. And now since Google is showing preference for AMP sites, this is imperative. I hope Yumprint catches up or we'll probably have to leave.