I wouldn't be surprised to find a few loose wheels, as I doubt that the design or manufacturing has changed.
I have used FVM wheels, and they're nice wheels, but I will probably stick with ESM. The main reason I changed to metal wheels was for rolling quality, and the ESM seem to roll better. As an example, I have a caboose, with ancient KD trucks, that generally resides in my staging yard.
Now, this yard isn't flat. For various reasons, non intentional, the middle is lower than either end. This caboose originally had KD ribbed-back wheels, with the flanges filed down. It ran fine, but would stay where it was left in the yard. I eventually installed Precision Masters plastic wheels, as they seemed to work better on some of my turnouts than the hand-filed KD flanges. It would still stay where I put it.
With FVM wheels, it would roll to the center IF I gave it a slight nudge to get it started.
With ESM wheels, it will roll to the center from a standing start, no nudge needed.
Both FVM and ESM wheels roll better than most plastic wheels, look better to me, and seem to track better backing up.
