(This is an early demo, but it gives you an idea how unique each platform really is from each other)
I think there is room for both platforms as they are totally different. Steem obviously is like a decentralized Reddit, and like the normal Reddit, there is a large fan base and lots of people that prefer the Reddit format. Synereo on the other hand, is totally different and is far more like some sort of mix between Facebook and Google Plus, and not anything like Reddit. They won't even have USD posted anywhere as Steem does. Profits with Amp/Synereo is something people would have to take a screenshot and share, unlike Steem, other than some visual indicators that a post on Synereo is popular.
As someone that moderates a crypto group on Facebook with 6600 members, Steem at first made me wonder if that would somehow hurt my crypto group, but, that is not the case. Since Steem has started up, my group is growing about 100% faster now, so Steem actually helps other social media connected to it. If Steem and Synereo bring more people into crypto, it is also possible they both could benefit, along with the users and traders of both platforms. In the end, I really think there is more room than people think, and massive potential for both platforms to grow and win! :)