I'm afraid I can only speak to the Bigfoot. Though I have lusted after the Airstream in the past, a hailstorm we encountered in Eastern Nevada last fall
changed my mind. The generic stickbuilt trailer we had at the time, suffered several dozen small dents from the dime sized hail that fell for only a few minutes. I have heard indirectly of Airstreamers suffering similarly so you may wish to check this out.
We've had our 21' Bigfoot for a few months and 4000 miles now. There is no question that it would be very hard to damage this trailer by hail as the exterior shell is very stout.
The Bigfoot has an extremely well engineered and built shell with more or less standard everything else. The rest of the exterior, door, vents, storage hatch, and furnace/refer/water heater, etc. access panels are generic travel trailer. This mostly doesn't make them worse, just not better. Fortunately, this stuff has matured over the years and seems to be of decent quality no matter what it's installed in.
Inside, the Bigfoot is fairly basic but the cabinetry is a cut above the crowd. I am guessing that fit/finish issues would likely favor the Airstream (but I *am* guessing).
Depending on where and how you like to "stay" (as ex-tent campers, I can't really say that staying in our trailer is really "camping" any longer), you may be especially interested in comparing tank and propane
capacities and what options are available for increasing them. There's also the question of additional batteries, solar
recharging, generators, etc.
Finally, as one who has been deeply into repairing water and rot damage on the two wooden framed trailers we've owned I would adamantly recommend staying away from all wood framed units, no matter how luxurious other aspects are. Without conscientious periodic recaulking and care, water *will* infiltrate into walls and under floors. This is sometimes due to poor workmanship, but more often is because of fundamental design deficiencies. In addition, look under the trailer. If the underside of the trailer is protected by a subtantial barrier (in the case of the Bigfoot, a solid one piece molded fiberglass panel that completely encloses the lower half), that's good. If it's the black or brown plastic tarp material that is common among the stick-builts, I'd pass.
A local dealer once told me that he offered his customers a $2000 weatherizing upgrade. This included going over the entire trailer exterior and caulking each and every corner screw, checking and fixing every missed staple puncture, and being sure that everywhere water could get in, there was a weep path for it to get back out. He was very proud of this service. He didn't seem to realize that he was presenting the very best reasons for not buying what he was selling.
Another dealer called when he saw the ad for our trailer in the paper. He was interested in buying it but wasn't curious at all in the quality job I had done in repairing the water damage. He was only interested if you could *see* any discoloration on the inside paneling.
Sincerest best wishes on your search.