SilverStone don't make their own PSUs, companies like Enhance Electronics and High Power build them for them. A lot of SilverStone's PSUs are very good indeed.
However the Strider Essential 500W SST-ST50F-ES that you mentioned is definitely an entry level product from them, as well as quite old.
Here is a review for it:http://www.sweclockers.com/recension/12226/7
What is your system and what is your budget?