I'm pleased you are asking this question. I was curious myself. My local Home Depot has quite a few of them right now and they look very healthy. I recently planted a Red Prince Weiglia and a Briant Rubidor. I was debating removing one or both and replacing with a Sonic. My only hesitation is that the flowers kind of looked messy if they aren't dead headed. With flowers that small it seems tedious. Also, I wonder if the spring flush would be as nice.
What I did do was plant a red clematis to grow into the weiglias so I can get some flowers later in the summer.
Regardless, I'm curious about how these are performing for people in their gardens.

Have only seen the red here so far, with fewer summer flowers than specimens at the same outlets of older cultivars that aren't characterized as blooming after spring. Definitely not continuous as seen here, with no flower buds on the new growth. In 3 gallon pot sizes.

OKay so it's been a few years. Anyone growing the pink sonic bloom and have a report?