144 - 135 = 9cm...
Seriously, each board has advantages. the 135 had great swing weight, worked really well in buttery water. The 144 is better when conditions are less than perfect, lands a little softer.
I think there is a misconception out there about boards being good, bad, big, small, etc. Just like you adjust your riding style to fit the wake (charge more on the rampy wakes, ease into a big pop on the steep, lippy wakes), you adjust your riding style to work with the board you ride. I have been on boards that I really had trouble with for the first few sets, then when I figured it out, loved them. I think alot of people write a board design off as bad when it is just a matter of learning to adjust the riding slightly. Of course, there are a few boards out there that are very difficult to handle, adjust to.