I felt the same way for a long time, but I have grown to love the new UI. I harassed every LogicMonitor support person for a year or more, telling them over and over that it was just terrible. But no more!
The current version does everything that the original one did, and much more. My favorite feature is that the UI allows you to easily set thresholds on virtually any grouping that exists in the system. You can set thresholds for any group that you can imagine (just keep track of conflicts!) The previous UI was often confused as to what group you wanted to set thresholds on.
The new device tree in the left pane is super powerful. I'd also encourage you to click around in the breadcrumb tail along the top.
Bottom line for me was the learning curve, since there are so many new features.