From the time I spent in the furniture industry, many years ago, bonded leather is better, basically the leather off cuts ground up and glued together, with similar properties to whole leather skins, but of course, cheaper. Not heard of PP leather, but you may mean PU? PU leather is a leather look plastic, and generally cheap - in the past it was sticky as it does not absorb moisture (sweat) and can peel after time with wear or in humid / warm conditions. I would never recommend PU leather.
Things may have changed in 15 years though!