Without you specifying your own goals, it's impossible to say if the SSB can replace straight bar squats or not.
The bar is built with nuetral handles on the front, which takes away shoulder stress.
It has a camber built into it, which overloads the upper back.
I would say those are the two biggest variables that make the SSB different than a barbell. For some good reading on the subject, check this out
Additionally, search for this article on google
"Elitefts Classic: Use the Yoke Bar / Elite FTS"