Is it more difficult to set up a break shot in 14.1 and successfully get through the rack and execute a successful break shot on the next rack or to run a rack of 9 ball vs the ghost?
Best evidence in 14.1 is Dennis Walsh's straight pool challenge at DCC.
http://forums.azbilliards.com/showpost.php?p=5800717&postcount=56
A little more than 60% of the time players got through the first rack with bih and with a new full rack players got through the rack 65% of the time but 8% of the time they missed the break shot. So in Dennis' competition in which players pay $100 dollars to get a dozen chances the success rate is somewhere in the mid to upper 50% range.
The best evidence I find in 9 ball is this study.
http://billiards.colostate.edu/resources/nine-ball_drill.pdf
I don't know where they got their data or on what equipment they are playing but generally speaking it appears to be considered an A player you need to run out vs the 9 ball ghost about 70% of the time.
It's inexact admittedly but it appears from this data it's harder to get through a rack of 14.1.