Having met Ryno (sdcdev) and had lunch with him, I can honestly say that he struck me as being a decent guy. 10/10 would have lunch with again.

I guess my three concerns with ShadowCash, in order of importance, are:

1. Proof-of-Stake is cryptographically unsound, in the long run. I know this is a hotly contested topic, and I don't want to flog a proverbial dead horse. Nonetheless, I have seen no cryptographic proofs (or assumptions under cryptographic models) to convince me that Proof-of-Stake is secure.

2. Being forked from Bitcoin is a blessing and a curse. Merging bug and security fixes from upstream Bitcoin (which will remain the target of more powerful proving and attack than any altcoin for the foreseeable future) is great, but it is going to be progressively more difficult to do so. The risk is exceedingly great that (as has just happened over the last few days) Bitcoin will reveal a security hole, and a cryptocurrency forked from it will not have implemented the fix.

3. Bitcoin's use of secp256k1 is...ok, but given that SafeCurves (Daniel J. Bernstein and Tanja Lange) view secp256k1 as unsafe, the use of the same curve is a little bit of a risk (Monero uses Curve25519).