I've had my Atlas 4.3 for a few years with different tire/axle combos, all with 4.0/nv3550. (33s & 3.73s, 35s & 4.56, 39s & 4.88)
First, the lower low range is not very useful if all your planning on doing is most Michigan terrain. You'll be in 3rd - 5th gear all day long if just bombing trails, or popping between high and low.
If you plan on going out of state to play in the rocks more than the occassional Badlands trip, then 4:1 is more worthwhile. For that, I've loved it. No more silly clutch slipping to try and climb, just drop it in 1st and let it pull. If I need to do faster launches, just drop a gear or two.
I think a doubler (or stak) is a much better solution for varied terrains. I've thought about installing a 203 in front of my atlas for that in-betwen gearing, but I really like my driveshaft length the way it is now, and don't want to change it.
I'd think about it if I went to a shorter engine and could push my drivetrain forward so my front driveshaft wouldn't be over 50" long, but not right now.