I voted for D30 because I just made the same choice myself. If my reasons aren't the same as yours, you may come to a different conclusion. I could have had a HP44/9" out of a '78 F150. Instead, I decided to build my 30/8.25 a bit seeing that my current tire size is only 32". With plans for running nothing bigger than 33's. Believe me when I say I would love to have something better, but budget has to dictate where I spend my money. This may not be an issue for some people, but I don't have the tools, training, and workspace to do fabrication or welding. I am also in an area that does not have a high demand for this type of work. This is what would make this kind of work very expensive for me. I am building up my XJ from stock for Moab this April, so I needed everything for it(lift, sye, driveshaft, tires, wheels, bumpers, rock rails, skid plates, gears, lockers, spare parts, recovery equipment, tools).
I could not justify the additional costs at this time to build a D44 over the D30. For my '99 D30 I bought some shafts, gears, locker, and install kit. If I had the '78 F150 axle I still would have bought shafts, gears, locker, and install kit. Add to that rebuilding everything on the ends(brakes, hubs, etc.) plus suspension(fabrication costs, track bar design, crossmember design, control links, narrowing, etc.).
Maybe sometime in the future I will have the need, not just the want to do this kind of upgrade.
Greg