I can honestly say in the GMT400's, I'd prefer the liftgate for the reasons stew mentioned, and the glass door in the gate for the simple reach in is good. BUT, when it comes to being a Morticians ride... for christs sake, use fuggin barn doors dammit.
I had to tow a Yukon a couple months ago. I didn't think much of it just cuz it's at the OU Medical Center, til I got there and then told go around back, it's on the ramp coming up from the delivery dock. WTF??? So as I'm loading it, I'm told I have to stop off at the Mortuary and drop off a body that's in it !!! **** THIS !!! WHAT??? I'm going to have a body in this bitch bouncing around on top of a roll back??? Well yeah, he'll be good and purged by the time we get him to the Mortuary. Morticiain tells me, you don't have to unload the truck, just set the bed down and we can unload it. So he goes in, some kid comes out, the roll back is at an angle of course, the kid opens the liftgate and kaboom !!! This body comes flying out on the gurney, and it was a big guy. The kid almost didn't get the brakes on in time to keep from the dude dropping on the ground. And man oh man, was that thing ever burpin' and fartin. I said, so that's when he meant by purged. The kid says, NO, he means fluids. This one will be a mess, he'll have fluids out of every orfice of his body. Nawwww, to hell with that. I've had no issues towing body parts around in cars from car accidents, but not whole damn bodies. That sucked. No lunch that day. Moral of the story, use fukin barn doors so you can open one door at a time and maintain your bodies without them rolling off the damn truck.