Two things make me not trust POS coins.

1. POS on it's own involves an IPO (high danger of scam).
POW + POS is perfect for pump and dump - buy up coins from miners (who typically sell low), once you have enough and pow phase is over proceed to pump and dump with less danger of whales dumping before you.  
There are also network security issues that I'm not well enough versed in to comment on.

2. Getting money for nothing which makes it worth... nothing.

Mining (electricity, hardware cost), running a masternode (expense of coins, maintenance, security) is work therefore has value. That's why the masternode proof of service model is better than proof of stake. It's also more in the interests of whales to run master nodes and secure long term earnings as opposed to just dumping when the price is high.