I've been eyeing this bra for months, but wasn't sure I'd be able to squeeze my boobs into it. So glad I finally caved and ordered it! I'm 5'3, 125 lbs, 30F bra, and the medium fits perfectly. I think the Intensity bra is a bit more supportive, but the X-Factor is still a great buy. Wore it for a deadlift and toes to bar workout and barely had to readjust. I'm super excited to finally have found a "cute" bra that fits and offers a bit of support.
Oh! BP customer service is amazing and was beyond helpful in helping me find the right size.