LK7, GLX, BUK, MPL, COL and others are no different than GRA. Having solo'd them all, its easy for me to see the similarities.
Some have many orphans, some are PoS only... all are very problematic. Copy n paste coins.. period.
In a sense all coins after bitcoin litecoin,ppcoin and primecoin are copy and paste coins as they bring nothing new. The question is how the coin is handled after it appeared. You have seen my short discussion with LK7's dev. Most of these clones have no ongoing support from the devs after the coin is launched. Here I found an active developer who I decided to join when he offered.
We know COL and some other are pure PoS, but GRA is both PoS and PoW, and both blocks are generating. Hope with new algorithm the diff will be behaving more reasonably.
I have to agree that PoW/PoS coins have a lot more problems than PoW only coins, but we are actively fixing issues so hopefully Grain will work fine for both PoW and PoS.
If that is really the case, then why is Peercoin, the first PoS Pow hybrid, so stable ?
Peercoin is using a different algorithm (SHA-256), and Grain and other most PoW/PoS coins you see in alt coin forum are some descendents of Novacoin.
The main reason, I think, Peercoin and Novacoin is comparably more stable, is because of its much bigger block time. Both have block time of 10 mins, as opposed to Grain, which is 30 sec. Clearly (for evident reasons), the more the block time, the more stable the network will be. Fast block time creates a lot of challenges, such as orphans, stability of blockchain etc.