Siacoin at least as a roadmap that looks like the devs are trying to do something with it. Reddcoin seems dead. If you are looking at any type of cryptocurrency, go to each currency's website, and look at their developer roadmap, and also the updates. See if they are making progress, or whether they are even updating their website with statuses. If you look and there aren't any updates for a year, you know to leave it alone, it's probably dead.