Current 0.4.4.7 testing branch runs pretty stable for now. This branch is available here for public testing:

https://github.com/novacoin-project/novacoin/tree/current

Basic list of changes:

1) Pruned transactions serialization support.

Pruned transaction records are now saved into coinsDB. These records are composed of 13-14 bytes of metadata (block height, coinbase/coinstake flags, block and transaction timestamp). This resolves all syncronization issues. Though currently there is no lifetime limit for such records, cleanup for old records will be implemented in the future versions of NVC client (this cleanup will be performed after reaching the 520-blocks maturity window, I guess).

2) Conflicted transactions handling.