It's good to see that everyone is waiting for the returning of PoS block generations. I hope everything will be smooth when we pass through the switchover block at 92000 in a day or two (pretty sure it will, as it worked fine in my tests).
Now I want to give you an overview of the issues with PoW/PoS so we will have a realistic expectations on the PoS.
From my experiences and my observations of many other PoW/PoS coins, the PoW/PoS coins are far less stable than the PoW only coins. The commonly observed problems are:
(1). PoW gets jammed (happened to many coins). Many fixed the issue by forking a new blockchain (including GRA), some did not bother to fix (or dev vanished?), like ADT and COL are still in PoS only mode.
(2). PoS stopped, like what happened to Grain, this is due to the out of sequence in time stamps.
(3). Lots of PoS generation affecting PoW block generation.
The issue (3) can be an annoying one. According to current algorithm, the PoW block time can be extended up to 12X the normal time, if there are a lot PoS generated in-between. This is a normal behavior to maintain the overall block time. And we don't expect PoS always generate a lot all the time (it's controlled by its own diff adjusting). Another possible issue with a lot PoS generation is that it might affect PoW diff, and cause orphans (and I still need to check the code to see why - my understanding is that the two diffs are separated). I saw this issue occurred with Lucky7Coin end of last year, it caused a lot of issues in mining (virtually all the mining pools are stopped as 90% are orphans), and most blocks generated were PoS blocks, with some PoW in-between (the PoW generated time increased between 2X to 12X). The problem is gone now after the PoS generation subsides in Lucky7coin.
The Grain is based on Lucky7Coin code (mainly to use its superblock generation algorithm), which in turn based on Novacoin/PPCoin. We adjusted many parameters and hopefully the same issue will not occur here. We also have all the fixes from PoW/PoS (like the fix from Balthazar on self-forking). For now we still allow the max PoW generation block time be 12X the normal one if needed. We could change it to less multiples such as 3X used (fixed by a patch in) Novacoin codebase, so it could make the mining of PoW less disruptive.
Anyway, just want the community knows the status of PoW/PoS coin in general, and let's hope the Grain will work great