The ES-16-XG has been around for a lot longer and is a "known quantity" - it's also much simpler to configure, and has four copper 10G-T ports (with some interesting interoperability issues that are mostly fixed by now AFAIK)
The MikroTik has better compatibility (it'll work with pretty much anything) and is a bit cheaper, but it's a new MikroTik product so I wouldn't count on it to be perfectly stable/reliable just yet.
My switch has been on since they released it in Europe and I haven't had a single fault or error yet.
If you're comfortable spending a few hours messing around with configuration and reading poor documentation and loading different firmwares, and you're comfortable with command lines and their weird approaches to some functions, the MikroTik is the better option. If you need 10G-T, a simple web UI, and better support - the ES-16-XG is the go.
You don't need to load different firmware, just update to SwOS 2.7 and you are good to go. I'll concede to your remark about documentation, it's rather horrible when you first look at it.
I don't know about you, but I feel that the UI on SwOS is very intuitive once you get to know what each tab is, and it's much simpler that the sub-menu hell that is an ES-16-XG.