have climbed in these shoes twice and so far I LOVE THEM! I can edge on anything, my heel stays put, the three velcro straps enable a perfect, snug fit on all areas of the foot. I cannot testify to the stretch of the shoe as I have not worn it long enough.
If it helps, I am a women's size 8.5 always. I bought these in a 8.0 us, which is men's sizing (39.5 Euro) and they were a little uncomfortable (for about 3 minutes) and after, felt great. If there is any stretch to them, which I presume will be minimal since they are synthetic, you may wanna take my sizing selection advice and go a half size down. I will most certainly be following up if they do stretch. In addition, I have a slightly wider foot than most women's so Evolv definitely caters to this.
Over all, I recommend theses shoes more than any I have tried (La Sportiva - Miura XS, Five Ten - Anasazi, Millet - D. Dulac Pro Model)