I did a ride on the July 4th weekend from SoCal to Moab, UT on the tubliss system.  No problems.  I did air down for the off road sections.  Because of the weight of my luggage I didn't go below 20psi on the front and 25psi on the rear.  I think I should have stayed at about 22psi on the front because of the extra weight.  I could feel the tire bottoming out on large rocks and bumps under braking.

I found an old thread, on Advrider, talking about guys doing a lot of long highway miles with no problems, so I just did it.  Make sure you balance your tire if you are going to do a lot of street riding.  Also I tried the "Ride-on" tire sealer/balancer product.  I don't recommend it with the Tubliss if you do a lot of street riding.  I had to use a lot more of the stuff than Ride-on's chart recommendation and more than their "extreme" recommendation.  The tires never really balanced out and when I slowed to a stop on the street, I could occasionally feel the tires go out of balance and it took several miles of riding before the tires sort of balanced out again.