i used...and still using pha pads in plastic backing that mike gave to me 2 and a half years ago when he wisited croatia.
in my case they didnt work perfect strait out f box, they needed short time to bed in and then started to work perfect, as somebody said, same performance on dry and wet, even mud and dust.
thing i have noticed is that they didnt produce same sound on all kind of rims.
when i got them i was using dx 32 and sound was wery loud, and then i switched to echo ( i thinh 2009...maybe 08) and they lost the sound, but remain performance, now i have try all hole rim and they have perfect performance but sound is not so loud like it was on dx 32. ( i know it also depends on what king of grind you use them)
about bite, i mounted them on fresh grind and they had great bite on fresh gring ( medium) and bite remaind great as grind becoming dead
wear life is one of the best thing, i use them almost 2,5 years ( to be honest i did put them in front for some time so it stopped wearing to much...but....) and now they are " finaly" dead with 1 mm left
i hope i coud help, and forgive me if ( i know i did) did grammar mistakes