It's interesting that the answers here are so varied! I have tried both and did enjoy using the Ojon but have found the PK range to really help with my hair. I wear it in a cropped bob. I have quite a lot of hairs but they are quite fine so they pick up static easily. My hair is quite wavy but heavy so it can flop easily and can frizz up. I choose, most of the time, to wear my hair straighter than it wants to by and since using PK elasticizer my hair has more 'guts', holds its shape better (both my own waves and the ironed-out version). It also keeps my colour much longer. So for me, despite the cost, it is good value for money. I spend plenty on getting my hair cut and coloured so if I can eke out another week or so thanks to PK then I am happy!
I should also add that I use GHD styling products so that may have some impact.