what i mean is that it doesnt have to be mikrotik but there are SFP modules for those one off connections. Finding a good modem isnt always easy and if you have a good router that has SFP it can double as a modem.
Depending on what you are trying to do the order of difficulty is ubiquiti < mikrotik < ubiquiti as a linux server. To properly use ubiquiti edgerouter you have to treat it as a linux server as the GUI is very lacking. So ubiquiti can be easier or more difficult than mikrotik depending on what you're trying to do. What i do like about mikrotik is that you dont have restrictions on your configs like you would on ubiquiti so you could have multiple layer 3 networks, put them all in address lists under the same name and you wont need anymore firewall rules than with just 1 LAN. It also lets you assign a DHCP client to the same port with static IP addresses so your WAN and LAN port can actually be the same. Ubiquiti wont let you do this.
I do run squid on my edgerouter pro, i give as many tasks as i can to my CCR and what my CCR cant do i give to the edgerouter in the form of a linux server. Saves electricity this way so getting both could be an option. Using a raspberry pi 2 as a server can help and it makes for a good driverless print and scan server aside from the other things is run on it and i power it from the usb port of my edgerouter.