Just an FYI. I just got a u50x and it seems lightening fast on UI updates and reports
This is not a fair comparison, but I was testing the lower u25 (older version and different class).
The one measurable item is flat out network speed. In my 1 GB internet feed, I was getting around 400 Mbps downloads from speed tests, but with the u50x, I was hitting 850 mbps . . . pretty much the max I get without an Untangle appliance in the middle.