steem is great. and its platform is outstanding. although it is difficult to gain Reputation (btw, feel free up follow/upvote me :) ), its clear steemit is gaining much popularity.
regarding investing in crypto, the best option (or at least the most safe) is diversification ;)
At the moment, crypto is all so closely tied to bitcoin, in fact most of it is only traded for bitcoin, that unless you want to daytrade, bitcoin is your best bet.
As for gaining reputation, it's all about getting comments. Lots of comments. It's harder to earn reputation points past a certain level, though, I notice.