Which option do you use in the Genie scout?

I know this has probably been talked about before, so if it has i apologize, give me the link to the thread and we can all move on, but i can't find it so...

In the genie scout what do you go by when seeking a player is it

1. Ability
or
2. Best rating

which one is better ?
one gives the player great attributes but i find the other (Ability) give you a better player?

Thanks

I take it nobody know's the answer to this?