Ups - they are a great width for a swap, very close to stock XJ width with the exception of wide tracks, which are not common in my experience. Also, they are D44's - an upgrade from stock.
Downs - many rears are off center, and that turns a lotta people off. The fronts are low pinion. Also, there are some vacuum disconnects out there that are not desirable for the same reasons people are not crazy about D30's that have it. There is a huge box on the driver side of the pumpkin that you can't miss if it indeed vacuum disconnect.