In my experience, where you get hurt with small wheels is the gearing. The typical solution today is to use the Capreo cassette/hub that has a 9-tooth sprocket. This allows one to use a normal crankset and achieve high enough gears for typical road riding. However, the Capreo cassette is a very wide 9-speed cassette typical of many touring setups. Consequently, you loose a lot of granularity with respect to a typical road bike.

Limiting the discussion to uprights -- my experience with recumbents is almost nil -- most people would describe the steering as a little twichy but one gets used to it quickly. Long story short, it isn't the small wheel per se that creates the effect but instead it is the relatively low amount of trail. So if you are accustomed to low-trail bikes then the adjustment will be very fast in my experience. As an aside, low-trail bikes generally do well with loads in the front such as a handlebar bag since it slows down the steering.

I have a Bike Friday NWT -- triple chainring with Capreo cassette -- and recommend it. The model has a more relaxed geometry and uses the more popular 20" wheel (ERTO 406) which has a much bigger selection of tires. I also suggest that you have the rims drilled for Schraeder and use presta adaptors since finding BMX tubes -- often Schraeder -- during travel is relatively easy.

At least with respect to the Bike Friday, some of the advantages are

(1) Packs/unpacks faster than S&S or Ritchey travel bikes. This is the consensus from experiences and discussions among the local cycling groups. Personally, I can pack/unpack both my wife's and my bike in the amount of time it takes a typical person to set up their full-size travel bike (~ 40-45 minutes from what others typically report). I am not a bike mechanic ... I don't possess any special skills that I am aware.

(2) Quick fold allows car travel without a rack. This both improves mileage and gives more options. It also gives a nice bailout option if you need to take a cab from the middle of nowhere. I can fit my wife's and my bike in the trunk of our Toyota Echo if I remove one of the front wheels.

(3) Bike Friday has a reputation for excellent customer service and will Fed Ex parts to you while traveling (24-hour phone line for emergencies).

(4) They do customize the bike such that it matches the reach and leg extension dimensions of your favorite bike.

I test rode the Airnimal. Nice ride but a strange tire size (24" ERTO 520).

I should note that my long distance riding is limited to centuries and double metric centuries. I have done many on the NWT.