I have grown accustomed to floating around while building, simply because I like the speed of moving myself rather than constantly moving my mouse over to the camera controls.
I'll hover in the same spot for a few seconds, to line something up, then fly over to another spot. Very quick for me and let's me see all sides. I also use a gamepad, so movement is a minor nudge of the thumbstick.
But with this new viewer has come a major hindrance. While floating I gradually sink to the ground. This never used to happen except at high altitude where you'd sink back to 200m.
The effect this has on my building is huge because during delicate adjustments I have to fight with the pace of the sinking.
Please, Lindens, if there was some reason for this change, at least give an option in the Preferences window to change it to the old style. I like hovering at a constant altitude.