Blegh... if you ask me, those Genia Bras are really crappy. The only reason why they make your boobs look better is because they have foam pads in the front. If you're looking for a better option in the stretchy one-size-fits-most bras, I'd much more highly recommend Bali's or Barely There's comfort-flex wireless series. Those are both EXCELLENT. I did a lot of trial and error with bras, probably because I'm stuck trying to find something in the elusive 42B size, so I ended up buying like 5 different ones, (including a set of Genie Bras,) and I must say, to me there's no comparison. Those two are the ones that I wear every day now. The Bali bras are much more stretchy, so they hug the shape of the body better and as such do not slide down, and the Barely There bras have adjustable shoulder straps, so they won't slide either.
Anyway, that's my 2 cents on the topic. I highly recommend those two brands. They're a bit more expensive than the Genie Bras, being just under $30 each instead of 2/$20, but to me there's no comparison whatsoever in terms of comfort. And the good thing about these generic-size bras is that, because they're stretchy, and designed to fit multiple sizes, there's no need to get new ones as the estrogen does its thing. So, yeah, I'd definitely recommend trying them out.
(And yes, I am wearing a bra pretty much every single day now even though I'm only 2 months into HRT. Sensitive nipples and leaning my whole body across poker tables all day to collect the bets that people don't pull in, is a bad combination. It definitely requires the extra level of stabilization and protection.)