bowlingmar,
Having owned both, I can easily say that the Oracle is the better of the two when you get on heavier oil. For a particle the Oracle gets decent length and I have not thrown it and had it NOT finish yet. The Throttle/R will have a stronger breakpoint but when there is carrydown the Oracle will cut through it and the Throttle/R will tend to skate unless it sees dry. Also, when it comes to punishing a pindeck----the Oracle beats down the pins much better than the Throttle/R.
Another point that I have seen mentioned in this post is the coverstock life. Roto's covers hold up well, as long as you keep the ball clean you won't have a problem.
Goodluck,
-EX-