I have the standard and the control ring adaptor , other than the control ring the pro’s are the same but the ability to easily customise the control ring to change the programmed exposure settings with EF lenses mounted is very beneficial and guaranteed to work with all canon EF lenses.
2) Having used a Canon film SLR for nearly four decades before going to DSLRs twenty years ago, I love being able once again to set my aperture on the lens - I'm a Manual mode shooter. This adapter adds this capability to adapted DSLR lenses.