Is Advanced and Supreme silicone worth the extra cost over the All purpose silicone?
I looked up ASTM-920 to see what Class-25, Class-35 and Class-50 meant.
Turns out the higher the class the more flexible and more adhesive your final joint will become. If you need the flexibility, you may want to go to a higher class.
There may also be a difference between the amount of biocide these caulks contain, allowing some to be more resistant than others to mold.
So in short, there does seem to be a difference.
If you have a shower installed on a flexible (wooden) floor, and this shower is used often, perhaps you may want to buy the most expensive one. For a basement shower that barely ever gets used and is installed on a stiff concrete floor (unlikely to experience flexing), perhaps you can use the least expensive.