If you properly build and maintain your strawbale home, you won't have a problem with bugs, mold, mildew, or anything else gross. Strawbale homes are excellent insulators from noise and the elements, hold up better than post and beam homes in earthquakes AND fires, and you save some on the costs of wood. However, the cost of wood is something like 10% of a home's cost, so don't get your hopes up. You can save in other ways by using cement flooring, salvaging building materials, and rounding up the neighbors for a weekend or two of working.
Have you noticed how shoddy the workmanship is on modern post and beam homes? My sister bought a new home last year, and they've had all kinds of problems. The contracter installed broken window frames, a broken bathtub, you name it. It's been about 8 months and they still have work to be fixed. This time it's the grout on the tile in their kitchen that needs to be pulled out and repaired. They even had to have the downstairs medicine cabinet pulled out and repaired. Seems somebody installed it at such an angle that would fly open when you opened it and it would whack whatever was in the way. It's a lot of little things that you notice after you've lived in a place for awhile. A post and beam home nowadays wouldn't last 75 years without a SERIOUS overhaul, so I wouldn't expect more out of a strawbale home.