What are you talking about? Surely you meant Prince's Premier with *Softflex* and not Duraflex? Now, do you think there is a difference when hitting with titanium tennis balls and with pressureless ones (or regular balls, if you don't know those)? Do they make a difference for you? To the softer feel, add some power for Prince's Premier and you have the two most striking differences (which have to count somehow with you first in order for you to rank them).