I will infer that the unicorn statement came from comparing her to the other options on STG. STG is like looking for a needle in a haystack. And unfortunately many of the providers use one of those needles. Many use ancient pictures that don't even look like them selves. Many are fugly as hell. Between looks, cost and personality, more often than not, mongers should just stay away.
Unfortunately many mongers end up thinking with the wrong head and they go ahead and set things up anyway. In these situations, buyers remorse kicks in afterwards.
Now, Ms Sweets is a mixed bag. She is definitely more attractive than the overwhelming majority of providers in STG. She seems to have her shit together for the most part going by the two times I've met her. But, everyone is not perfect. We go into things thinking with our little head because we have needs that we want met, now. And when a curveball or a speed bump happens like getting ghosted or blown off, we react accordingly.
In general, compared to her competition on STG, I would hypothetically rank Ms Sweets in the top 10% compared to the dredge that advertises on that site. Does that make her a unicorn on STG, yes. Does that make her a unicorn compared to all of the various workers in the industry, no.