Searching the net i couldn't find much on these filters and if they were any good, other than they are cheap on Ebay and come from Hong Kong - sounding highly doubtful. So i took a chance and bought the Tian Ya kit for approx. AU$40. It included a holder, an adaptor(of your choice) and 4x 84mmx100mm filters.
Here is the kit on ebay
It is basically a Cokin P system for half the price of a decent filter. The holder is just plastic and feels cheap but fits well to the adaptor without being to loose(better than the Cokin WA holder). I'm reasonably impressed with the filters/glass as they look good quality with well cut edges and come in their own individual cases. They slide onto the holder(which holds 3 filters) well except for the middle one - quite loose!
This is very comparable to genuine Cokin(P only), especially for $40, you'd be lucky to get the filter and adaptor, let alone filters for that! The optics of the lens seem un-effected as far as i can notice. The only problem i guess is the GND which is only a soft gradual grey(Cokin seems to be the same - not true ND) and the overall cheapness - you may think you need to spend more to get more?
Either way it is a cheap way to start out and get some experience in the world of filters and effects, if your interested in that kind of thing, and you can always add to it with better/different filters.
I recommend it to anyone on a budget!
(Just to note: i'm not a sales rep this is my personal review of the product and have done it in hope it may help someone else)
Pics of the actual kit.. i'll post some samples in a sec.