Basically all of them are fine coins with fine projects with perfect industry top blockchains. IOTA has currently really developed blockchain with many project integrations. NEO is gonna be a new ICO standard blockchain with these NEP5 tokens, but Ethereum is much higher competion. TRON on the hand is only developing its product, but is gonna much better than NEO in my opinion. I would recommend you buying NEO, IOTA in short/medium term and TRON in long term. Good luck!