As a current PPL student I can't give any personal experience of the whole course yet but I have something to contribute that relates to the question:
I started mid August this year and progressed rapidly through the General Handling phase onto Circuits. All going great and getting lots of praise about my ability as a pilot. One day my usual instructor is not available and so the CFI steps in his place (not as a presolo check but out of courtessy). This is only the 2nd lesson I've ever had on circuits and I've 7hrs TT after the flight with the CFI. The CFI tells me to write the airlaw exam the very next day and I can go solo the next day too! I was seriously chuffed about how fast I had achieved the go ahead for solo flight.
But then...
I didnt think I could write the airlaw so soon so I held off and booked another lesson with my usual instructor. For various reasons on this lesson, and for the first time in any of my lessons, my instructor found fault with my flare during the landing. This experience seriously knocked me and now I'm sitting at 15hrs still not having gone solo and I've spent loads flying with the same guy doing nothing but looking at the flare. I realised after a while that this was just the way it was going to be if I stuck with that same instructor so I organised a lesson with another instructor. Low and behold I can suddenly flare properly again! The new instructor had taught me more in that one hour lesson than the I had learnt in the previous 7 hours focussing on the flare alone. We did all sorts of things, not just the flare and that helped take my mind off overthinking and obsessing about the flare. I will no longer try to stick with the same instructor, in fact I will try and get the input of as many instructors as I can. Having input from many sources can only be to your advantage as a student pilot - its the same as having read widely vs just a single textbook.
So from my experience some of the hours that people take to complete the course can actually be influenced by the instructor/student relationship. I dont believe its ability alone that determines how long it takes you to complete the course. Annoyingly it cost me quite a bit and wasted a lot of time for me to learn this!
G'luck with your flying.
splatt