I bought one of each when they came out. Both shoot very well with a slight nod to the 619 in accuracy. The two-piece barrels got slammed badly by breakage problems experienced by a police agency. There was lots of talk on this forum about it.
If you put a bad product out these days the internet will destroy it quickly. The only hope to save it seems to be a total recall. However, the market for 619s and 620s is so small S&W apparently chose to drop the product.