Hi Mary,
the two themes are, as far as I can tell as an outside observer, only a "Work In Progess" in the sense that they keep getting better, and at a fairly rapid pace. Lots of people have been using them in production with great success, and I'm putting my money where my mouth is on this one as my institution will be using Elegance from this summer onwards.
Julian has mentioned before that the large numbers of excited users wanting to try his themes, and then struggling with the basics of installing a Moodle theme, gives a false impression of their maturity to those just skimming the forum and seeing a bunch of posts titled "Problem with Essential". As a forum moderator, you should know that these "bugs" are primarily the result of enthusiasm for the theme, something that anyone interested in the future of Moodle should welcome (even if they can be a bit annoying when they provide little
context for their issues, and are often the same simple problems over and over again).