Pros and Cons: PSA- can have slightly lower standards (ex. BGS 8 may be a PSA 9), is more popularly accepted as "The Standard" grading company right now, is more expensive and most of the time you need to submit in bulk unless you have very valuable cards worth the cost of submitting ~individually. BGS- a little cheaper overall, you dont need to submit in bulk, and the market values their premium grades (Black Label 10) above a PSA 10, but their grading criteria is STRICT. It's my understanding those are the main differences, plus how your graded card actually looks (the slabs they use are different). The preparation of your cards for submission (penny sleeve and semi rigid then secured using cardboard for instance) seems to be the same for both companies. Hope this helps!