PFsense has an amazing GUI. what problems did you experience?
Compared to my experiences with the Sophos UTM, it's downright painful. With the UTM the UI elements of every part of a service are grouped together, and are duplicated in sections where it's intuitive to do so. Eg Certificate Management can be found in multiple places in the UTM but all things related to the web filter are in one place, all things related to routing are in one place, et al.
Luckily they are redesigning the GUI for the next version, I'm hopeful that they will rearrange it as well (even though that will obviously be awkward for everyone already familiar with it) but I don't know, haven't paid attention to the development.
Case in point: Reboot, shutdown and Backup/Restore ought to be under the "System" menu, right? Nope. It's under Diagnostics, which is a large alphabetically sorted list (not by functionality or anything else, so if you are unsure of which term was used, well, you're better off consulting google).
I much prefer to support PFSense because they seem more supportive of their community, I will be looking forward to trying out their new UI when its out!