Have had this plant for a season and a half. It is a vigorous producer of new stems compared to most hydrangea. Mine was killed to the ground in the Polar Vortex in zone 6B, but has rebounded with 40+ new stems. As with most new wood bloomers and rebloomers, most growth this year following the vortex came in the form of thick stems and large leaves with few blooms. There were around 5 total blooms around the base/perimeter of the plant, but that was it. I'd expect a lot more after a milder winter. The bloom performance was on par with staples like Endless Summer and the Let's Dance series, as nothing across the board bloomed very well this summer.
I believe the advertised size should be bumped up a bit, since mine has grown from the ground to a height of 30" and a width of 50+" in one season alone. I'd imagine milder climates could see one of these reaching 5x5'!