It's a piece of cake. Ride is substantially improved due to, in part, lower air pressures. Haven't tried to find one on the road in an emergency, though and can't yet speak to any wear comparison.
Wheels, tires, studs, nuts and covers must be changed. Studs knock out easily with BIG sledge hammer. Alcoa now makes a nice i-piece hub and nut cover. I have only done the ft on my '99 XLV (IFS); no shaving of the foam was done at time of installation but some is being worn away. Removal and installation of wheels is a little tricky with hard fiberglass fenders. Cost was $3000-3500 for the pair.
CAUTION: New wheels are hub piloted as opposed to the original stud piloted on the XL's. My bus (1999) had hubs suitable for hub piloted wheels already installed. Verify your hubs will accept hub piloted wheels. Not sure where the break point is...maybe disc vs drum brakes?