I don't think I've ever seen somebody asking for advice as to whether to invest or not... you'll likely encounter a lot of varying opinions and whether or how you invest really depends upon your objectives.
Whether Steemit is decentralized is debatable, primarily due to the voting power of UPVU (bidbot) and the steemcurator accounts run by Steemit Inc (TRON).
If you simply want to make money, then you can buy some STEEM, delegate to UPVU and post something everyday to get your upvote. Whilst I'm not a fan of this approach, UPVU ties up a lot of STEEM which doesn't get withdrawn. The downside, is the sheer volume of crap content that fills the Trending Page as a result.
If you want to support authors and do some manual curation, you'll be a rare find. There are very few whales that manually curate, possibly due to the difficulty in finding good quality content. If this is the route you're thinking about taking, my suggestion would be to spend some time trying to find content that you'd like to vote on or alternatively, become active again without the "weight" of investing.
Whilst I'm currently only active on Steemit, I have also used Hive and Blurt. Hive has undoubtedly got the best content (for a native English Speaker) and I believe the Blurt has the greatest potential although some significant stakeholders have recently left due to a disagreement with the Blurt foundation.
As for downvotes, they don't really happen any more. Possibly due to the passive nature of the community now (in the main, people have accepted that there are scammers (which some people tried to fight)).
So really, it's a question of what you want to get out of it. One of the other replies mentions the effort people are going to to please investors. In my opinion, this is to the detriment of blogging and on its current trajectory, I see the reason for genuine bloggers who write good content slowly decreasing. I've written a bit about it in this post which might be of interest. If you do decide to come back whether you're investing or not, it'd be nice to hear what you think.