1) One of the best security
2) Better distribution than most (QRK audit is still going on by community... check here: http://forum.qrk.cc/thread/368/auditing-block-chain -> 30% of coins in ~30 wallets, that is actually very nice)
3) Nice amount of coins (you can buy everyday items with reasonable numbers, when coin matures)
4) Support of Bill / Keiser (this IS important, can't get around this)
5) Small inflation coded in (coin that is mined out dies, small inflation means more stable)
6) Very active community -> best reason
It is 1 million extra Quarks every year... so in theory in 1000 years there will be 1000 million more Quarks. But the idea is, that not all Quarks survive and the actual number will remain roughly the same or slightly more. This means that miners will never lose interest and network will remain secure.
Another reason why QRK is good.
7) Quark is CPU mined (this means that everyone can mine it, not only large ASIC farms)
I found great post in Quark forums that explains so much: http://forum.qrk.cc/thread/337/quarkcoin-summarized