I prefer to invest in coins that have a highly useful and unique platform behind it. Ethereum has one, but it seems like it is mostly geared towards business, and something tells me that, with the price of ETH going up, it's going to get harder for companies to actually be on their system. Not an expert though.

BTC also has a useful platform, but it is also quickly getting competed against from all angles. Litecoin, for example, can do everything Bitcoin cn do, but faster.

See where I'm going here? Gotta look at the longterm applications. So I'm VERY confident in STEEM (Everybody needs to get as much Steem Power while it's still affordable). I also hold a bit of Litecoin, Dash, Golem, Factom, Antshares, Iota, and a few more.

But yeah it's a must to research these development projects and their associated coins as much as possible!