What Scrypt-coin they mine over there? any info?
why you must buy KH/S with BTC not
THE same
coin that being mined ?
What pool this service use?

any one care to add any information ?
The admins said they mine the 3 most profitable coins, this could mean a few different coins; not sure if they mean coins such as DOGE/LEAF, but it could also be GLC, GLD, FST, FRK, etc (that's my guess)
I'm also guessing you buy with BTC because it's "universal".
You get paid in BTC...if you decide to re-buy more KHS, it'd be weird if they paid you in those coins.
They mine the coins, trade them on market, and pay out in BTC.
If you paid in the same coins that they're mining...it's more hassle for them to receive the coins, then trade them, then pay out...does that make sense?
Not sure what pools, that's a good question. I should ask one of the admins when I can.
....snip...
who make the mined coins choice? the service admin's?
as there will be atleast three or more coins to be mined by them at any time i think it wont be one pool, and harder to track their actual hashpower in action.
Why not add LTC to KH/S trade market with BTC ?
suggestion 
make sense too, also why not give the user choice to get paid in BTC or the mined coin? if the coin is profitable and have future it will be an investment too.
Overall a good idea and a competition to the scrypt market
With more user hope that the trade price will be more better.