Soda blasting is much more gentle , and does take some time .
Sandblasting causes so much ablation that it's not really recommended for many/most antique items .
Sand/soda/shot/bead blasting results do very much depend upon the skills & attention given by the blast operator , as well as the quality of the blast mat'ls & equipment .
Blasting does produce very good-to-fair results on rusty metals (cars , ships , etc.) and buildings , but I consider blasting the first option for the impatient .
As D&b mentioned in a post above these , stability of metal is always a consideration with many antique metals .
Heat & ablation can cause small-to-large portions of a metal object to crack , break &/or to be lost forever .
I'm for slow-and-steady 'winning the race' , rather than quick used-for-production methods (while refinishing/restoring antiques) .
That's just my cautionary opinion , though .