According to the opinion on most reviewers, the BGS is good for autographs, rookies and refractors.  The PSA is preferred my most football, baseball, basketball cards collectors for its grading system.

The SGC is also preferred and ranked highly for football, baseball, basketball cards.  The GAI is also good for football, baseball, basketball cards. It is good that you read visit the grading companies’ websites to learn more about how it grades the cards it collects. Some companies determine the value of the card according to the player imprinted on it.

For instance basket ball card containing Michael Jordan may be more valuable than the one containing Luc Longley photo.