This bra didn't work for me because of the underwire/band configuration. The cups sit too low for my high-set breasts.
The cups seem to run true to size and the band (at least on an unworn bra) seems to run about a size small. The 30GG fit more like a 28H... but the band seems like it might stretch quickly.
I ordered the Isabella because I was in desperate need of an ordinary (and black!) T-shirt bra and this one was for cheap on eBay. It turned out I misjudged my size (again...) and would need a 30H, as the 30GG have me a bit of a quad-boob. Not much, but in the end I decided not to compromise and sent the bra back.
Apart from the quad-boob problem, though, I was pleasantly surprised. The bra fit flawlessly everywhere else and the support, uplift and rounded side-shape were awesome. I've only owned two molded bras so far, but they were by no means as comfortable and soft as this one.
I tended to avoid molded bras up to now, thinking that they would just make my boobs look bigger, but I've changed my mind. If I find the Isabella in a larger size, I'm definitely ordering it again.