Having posted in the alt-coin forum here (I'm still pretty convinced that ETH at least will be around for a long time and is very safe for a cryptocurrency), I am getting mixed signals.
usually people say things they have heavily invested in are the "best". there were even people here who pationotely argued that gold is the "best" and bitcoin will never reach parity.
what you need to do is to study each option yourself. for example try downloading and running an ethereum node (not its simplified light wallets but the full node as you would in any supposedly decentralized cryptocurrency). try sending and receiving some coins.
check the economy of that coin (inflation, supply, premine, bugs, roll backs, scams,...).
you can also use bitcoin as the reference. for example compare bitcoin supply with ethereum supply. bitcoin cap with ETH cap (or lack of cap) and so on. then decide if it is a good long term investment or not...