All I can offer as a newbie myself is, when I saw the two side by side, it was a no brainer. The difference in size between the two is dramatic, and having the extra space is really nice. If you have a small cook, look up some of the fuel saving strategies where you run a ring of coals partially around the perimeter of the ring, which might help as well.
While I can't judge on the comsumption part between the two, I do know that when I used my DigiQ DX2 the first time last week, the consumption dropped ALOT. I'm not quite sure why, but I probably used 30% less than usual. That said, I will echo an earlier post that I also wired my ring to the grate, and put some big handles on the grate as well, and after the cook I immediately close all of the vents, and later I will shake off all of the ash, and leave the unburned portion of the coal for next time. So you save there as well.
Overall, I think we have to understand that by the time you buy all of your supplies, wood chunks, charcoal, meats, and factor in your time, BBQ'ing your own is not a financial ROI thing. I can get pretty darn good BBQ locally at a price much cheaper than I could ever make it for, so it's all about the enjoyment factor. With all of the mods, and extra's I've bought to get rolling, I'll never in a million years amortize that, but that's not the point. It's all about eventually becoming the best damn BBQer on the block (and beyond)!