I think replacment cost is high on both the Rizomas and the KTM Rearsets.
The PP Tuning ones are still my favourites and I prefer the way that both the gear and brake levers move with the footpeg so the action is always the same no matter where you move them to whereas the brake lever on both the KTM and Rizoma doesn't move only the foot peg moves and the stub on the end of the brake lever, I also think that having the bearing on the footpeg mount also means that ergonomically speaking it works with the same motion as your foot and so would be a more efficient action, although that's just my thoughts on it and not from any scientific research.
Of course the price for doing it that way also means you have to move the master cylinder and reservoir.
I think they're all nice though and I'm sure whichever you pick will do a good job, unfortunately I've no idea how much the replacement costs are on the PPs compared to the others but considering how much cheaper they are to buy the set I'm guessing the parts will be pretty good too.
http://www.pptuning.cz/en/shop/products/item-538f 