Here is my experience...
im learning pd before i buy max/msp , since pd is a lot like max but free and there is a whole lot more documentation on PD than max, and the people who developed PD are the same people developing MAX (from what ive read) i figured id learn PD before buying MAX.
This has a lot to do with me buying Reaktor 5 before i learned programming and hated myself for years for that and ended up using the library and almost never opened reaktor after that.
After about 3 or 4 months of annoying reading on PD im on my way to building my first FM synthesis drum machine so yay! i dont feel so stupid now and studying on PD is making me understand Reaktor 5 so im guessing itll help me with max/msp as well.
so take it from someone who made an idiotic choice on purchasing software about 2 years ago based on who is using it, being a fan of richard devine and datachi and electroacoustic music.
Software wont make you sound great only studying hard will.
PD is a great place to start and im guessing itll be a great place to stay...
hope this helps.