I just scraped, smelled, and ate the rind of a sunquat I had sitting in my fridge (it is not really fresh anymore, been in there a month)
The rind is slightly lemony, but much less so than any true lemon or citron I've tried. I don't detect any hint of the Meyer scent, it is simply "very weak lemon" rather than "something other than lemon" scent/taste, like some other kumquat hybrids the skin is rather bland instead of sweet like you might hope.
Overall the fruit is a poor substitute for a lemon, however if no lemons were available I think people would be thrilled to have it. But if you can get true lemons don't bother.