If the coin is closed source I would be skeptical. Even open source with closed source components is very shady for a supposed decentralized cryptocurrency.
XRP is controlled by CEOs.
XRP is bullshit
Mastercoin is not very popular, very little was created. Built ontop of bitcoin.
Nxt has an army behind it, but there is skepticism about distribution.
XCP is a lot like mastercoin, built on bitcoin. You essentially destroy btc to create xcp. Different type of distribution