I just moved from a SRW to a dually. Not sure how but when loaded my SRW was almost at tire capacity and almost 1000lbs over GVW. This was with a 9' camper. I camp a lot in BC and they can scale you, they go by GVW... but I believe it is a very rare occurrance.
I like not even having to think about it with the Dually. I really had no adjustment period getting used to the width but the length is a different story. I am actually sort of regretting not going to a 450 with the wide track axle and much tighter turning radius.