Mate i've tried the Jt emotions and altoughth they're a good idea they are really uncomfortable to wear. I suggest sticking with the tracers and getting some rase skid knees or other type of trouser with skid knee's cause i can skid for 10 metres over rough surface with them.
Also another question...
why do people wear knee pads on the outside of their trousers?
not only does this make them look silly but also doesn't really prolong the life of their pads does it?