Last week I wiped my Storm and loaded OS 4.7.99, so far it's been good. No real problems with speed or being laggy. It did lock up the other day when I was trying to find the Illinois Emissions testing center. I was switching between the browser, VZnav and google maps, so I guess I can understand that.
At this rate I might keep it for more than a week before I go back to my Curve.