After my last offroading trip, I had a shattered front diff, so airing back up was the last thing on my mind. Besides, I was putting the stock Duelers back on anyway.
Now the BFG MT 33s are back on and I just drove from Boston to Rochester, NY at less than 20 psi. The ride is a lot smoother, but also a lot more loose in the turns, and the straightaways for that matter. Also, the lower your pressure, the worse your mpg will be, and your tires will also wear differently, if not quicker.
I'll be airing up before the ride home, probably to around 30.

Brian