Coming from a person who has had both types of trucks LWB and SWB, I can tell you that there are reasons for both.
If I did not have an exact need why I need a LWB. I carry a motorcycle and pull a camper and with a SWB I would have to leave the gate down and I can't pull the camper with the gate down.
Other than that, hauling lumber every so often is not a good enough reason for me to get a LWB.
I have a LWB and to be straight forward, if you live in around a city, they are a pain in the butt. As it is with this LWB. I can no longer get out of the bakery and store parking lot in one shot. I also can't park in my daycare providers driveway, there's not enough room for me to get in an out. SO I need to load my kid in and out on the street.
at least a half dozen times in the last 3 months, I've gone down a dirt road with my truck and couldn't get enough room at the other end to turn around and had to back out, a swb would have been able to make the swing.
If I didn't have a specific reason for a LWB, I would get a SWB in a second. The LWB is alot of truck.
Nick