SooSoo production quality is better than Sideshow. Heck, at this point even Threezero has better production quality on their figures. Sideshow is the only company (along with Star Ace) in the 1/6 figure game that hasn't improved their production quality since they started. Honestly looking back at Sideshow releases, they might have even downgraded over the years.
SooSoo's production figures are as good, if not better, than their prototypes. With Sideshow, it's a 100% guarantee downgrade going from their prototype to production. It's sad and is unfornately to be expected at this point with them. They increase price but show no improvement in quality for it. Their production sculpts will never not be super soft compared to their prototype.
I wish Sideshow would actually look into improving their 1/6 department but they seem to not care in doing so.