Update: I picked up our F-550 Lariat on Friday.
The 750 mile drive home was fun with 10 unloaded leaf springs; my kidneys should stop bleeding in the next week or two
We needed the 19,500 GVWR as I'll be carrying 8000+ lbs in the bed for a custom built setup with Eagle Cap 1165 (triple slide truck camper) on 43" tires (think earthroamer).
We moved from an F350 with a GVWR package (14,000 gvwr) with a Northern Lite 10.2 in the bed.
For you Gents discussing trucks; generic rule of thumb:
F450 is for pulling stuff.
F550 is for carrying stuff.
p.s.s. Progressive insured it for 1/3 of what Geico wanted.
Private use of a commercial vehicle.