We've experienced fading idle and occasional stalls on brand NEW bikes, but after the break-in - with properly set idle - the problem was not present anymore.
These bikes run significantly better after 1,500 miles. The Enfield is a thumper, so you can feel some engine vibration (thankfully!) but it's really tolerable up to 65 mph, viby between 65-70 and feels a bit unconfortable over 70.