Stay away from low value master node coin which could later scam investors have nothing to do with stay away from all master node project but due to the fact almost all master node coins go from grace to grass, the best way to advice a newbie is to stay away from master node project because newbies will not understand the features the look out for before choosing a master node base project.
Beginners should stay away from all the altcoins not just masternode coins because almost all of them are useless specifically the top 20 altcoins that are the most hyped up and most terrible coins created for pump and dumps.
I understand the hype base of the altcoin market make it hard for investors to understand the altcoin that performs genuinely well in the market but if we are talking about altcoin that included ETH which was another project that introduced new features to the crypto sphere (through the smart contract/dApp scheme) and I consider it not to be among the terrible coins you said.