To-may-to, to-mah-to. Po-tay-to, po-tah-to.
Perhaps the more likely comparison would be apples and oranges. This is the precise problem encountered when looking at the original Vatican document and those that were released by the Nunciature to the USCCB (continenter vs. stabiliter).
Thank heavens, the Vatican is finally issuing a clarification/directive for implementation of the motu proprio "Summorum Pontificum."
Thank you, Holy Father, for your continued "shepherding" of your flock.
Yet another reason to love our German Shepherd!