I've heard of ETH, but what the hell is a lisk, waves, decred?

Let's say hypothetically that you want to invest a lot of money in a cryptocurrency other than Bitcoin. Which one do you pick, the new hyped-up flavor of the month with God knows how many potential security holes, or a long-standing and established currency that has been around for years and undergone security audits?

Bitcoin fits both those descriptors, as does Dash. Eth fits one. The others...they fit none.