Mikrotik suffer from a gross amount of "Not invented here" reinventing existing open source protocols such as OpenVPN, a custom sshd and web server, and it shows with their amount of issues (how many years has it taken to add UDP to their OpenVPN server?). In some ways I think their no better then UBNT in some ways.

Tell you what. I used to have a Mikrotik CRS125 switch in my home office, and by default if you have a set of ports where one has no VLAN assigned, and the others have untagged VLAN assignmnets, any broadcast traffic on the untagged port(s) without a VLAN leaks to the ports with an untagged VLAN. This isn't well documented in the manual, and to fix it you either disable "Invalid VLAN Forwarding" (I think) and/or move said ports without a VLAN to a VLAN.

Many of Mikrotik can be loaded with debian or openwrt, its hardware is solid

My CRS issue suggests otherwise (could just be CRS), but ignoring OpenVPN I haven't had many issues with RouterOS. It's good to have the option though.