Nxt does not suffer from the nothing at stake issue and I'm not sure that it still uses checkpoints either.
Are there Nxt bots or something that scan the forum for the terms "PoS" and "Nxt" and send alerts to the Nxt pumpers? It seems you can't use either of those words without attracting them.
Anyways, last time I dipped my toe into the PoS debate,
that very day Cryptsy's Nxt node went down apparently due to a blockchain convergence issue. I entered the Nxt thread and found this jewel complete with the bright-red 20pt font formatting:
Okay, guys. I need to bother you once more:
Please update to 1.1.3 as 1.1.0 is somewhat broken.
Maybe that's the problem that cryptsy us having is there transactions are not going through. They might be on a fork.
Anyone let them know, please.
Ah, yes. And they should tell me if they wish to be added to our future update-mailing-list .
I found the nonchalant manner that the network fork possibility was dealt with quite telling: just send out new updated code and make sure you join our mailing list!
Anyways, if it is true that checkpoints are now eliminated, then the cabal of large Nxt holders could very likely sell their coins but keep the associated private keys, wait a while, and then launch a nothing-at-stake attack to reclaim their coins.