I'll post my experience too, 96' HDJ80, 1HD-FT, H151F, HF2A
After quite a bit of debate and research, I elected to install the Trail Tamer 10% OD gears and also the 3.1:1 low range gears when Valley Hybrids was having their Christmas sale. I also went part time in the case and installed a Marlin spool and Aisin hubs. I did have some doubts because many had posted that they hated part time for various reasons or that AWD was simply just better.
Once the gears were in, I did a trip yesterday to Eastern WA. I fueled up at a station near the house and at the end of the trip, re-fueled at the same station using the exact same pump and method. In total, it was 330 miles of driving and I went over three mountain passes (Snoqualmie 3,015', Blewett 4,124' and Stevens 4,061') At the end of the day, fuel economy was 24.47 mpg which is a 20% INCREASE over what I normally was getting. Not only that, but the OD transfer case gears essentially net a 28% OD using the H151F and the engine seems to be operating much more comfortably in it's torque and powerband. All the driving I did was between 55-65mph on stock sized tires and stock 4.10 axle gears. I pulled all the mountain passes in 5th gear at about 55mph and EGT's sat at 900-1,000 with boost right around 15psi
If you're considering the OD transfer case gears or going part time, I'd highly recommend it. Neither my wife or I have noticed any handling differences although I will be more careful when it's slick out.