First, a disclaimer: I was PPCLI for 14+ years.
I joined the PPCLI because it was based in the west where I wanted to live, had a battalion at the time in Germany where I wanted to serve, was a regiment I had exposure to as a reservist, and was the regiment of a number of officers and NCOs I had met and admired.
The PPCLI, the RCR and the Vandoos are all very good at what they do. However, you are right when you suspect that there are cultural differences between the regiments. In fact, there are very noticeable (and somewhat unexplainable) cultural differences between battalions of the same regiment.
I served in both Third and Second Battalions of the PPCLI and my personal feeling was that 2nd Battalion lived by the "work hard, play hard" philosophy. This sounded great, but it sometimes could get out of hand. 3VP, on the other hand lived by the "we have fun doing our job" philosophy. There, you were allowed to have fun at work. Both were equally adept at their soldier skills. Personally, I preferred the 3VP approach: I was good at my job and enjoyed doing it.
My sense of the RCR, having worked with many excellent officers and NCOs from that regiment: they are also very professional -- but they seem to display a more powerful awareness of history, and take their role as Canada‘s "senior" infantry regiment very seriously. Personally, I thought this made them (as a collective group, not necessarily as individuals) occasionally slow to adopt new thinking and changes to time-tested procedures. To wit: battle drills -- while the PPCLI were developing new section battle drills, the RCR (it seemed to me) were hoping not to have to give up "sections in line, forward march, left foot -- bullet."
Just one man‘s opinion... I‘d be interested to hear thoughts and perspectives from RCR and Vandoos members.