Masergy is a great tool, however I don't know if it distinguishes itself apart from other VOIP tools. I believe Masergy would be more effective for end users that dial out often. I typically have meetings and use another tool, so Masergy is only used usually a few times a week for me.
Clunky UI in some areas - Settings for example. You have to drop down boxes to get to your audio settings. This is time consuming while trying to fix your audio devices.
No easy way to switch audio devices.
No 'universal' text box to type a number in to dial. You have to click a tab. I sometimes type the number in the 'What's on your mind' box accidentally.
Masergy and Skype for Business are somewhat comparable, however Skype for Business had the additional functionality of chat, which was used quite often. Now that Skype is part of teams, it makes that product stronger. With teams, all my communications were internal and with Masergy my communications are external. I believe they pair well together, even with some overlap.
