There are no best or worst coins. it all depends on their supply and usage in general, and sometimes the advanced features and implementations. The higher priced coins like, LTC, ETH, are not cheap but they are more stable for investments. They will give you good profits if you hold them for sometime.
IOTA is also a very feature rich coin and it's best to invest your money on this coin and hold it for sometime. Digibyte is also good but not as good as IOTA. I would not recommend you to go for ripple because its supply is very high and it will not give you good profits. If you are really into the investment game than for now you should go for IOTA.