We have used one of these saws here on the farm, while building log structures this past season, and can state that they are well-designed and well made. Of course, the chief reason for the folding designs is the ease of portability, and you do not need one if you stay put in place. But while on a move (for example during a wilderness adventure, or a permanent journey from a city to some more convivial place in the countryside) compactness is a blessing. In winter survival-like situations (while your hands may be nearly frozen) Bob's saws fold from traveling (photo 1) to working position (photo 2) in seconds without any need to screw around with nuts; hands clad in mittens are perfectly capable of the job.
One note:
The blades included with these saws are made in Portugal, and in line with what has become an international standard, they too are "point-hardened".
This prolongs the period of initial cutting efficiency but also makes the common files useless as tools for their further maintenance.
The USA- or Canada-made re-sharpen-able buck saw blades have been swept off the scene by Father Progress approximately 20 years ago. The modern versions (whether made in Sweden, Portugal, China, India, Mexico etc.) are now all "replaceable" -- meaning you should throw them away once they get too dull to meet your personal standards, and buy a new one. (There's no need to be that wasteful, however. We shall address this issue in the forthcoming section on "tool maintenance by the owner". In the meantime if any of you are aware of a company -- anywhere on this planet -- that still manufactures "re-sharpenable" blades please let us know.)
He makes the aluminium model also in 21", (and occasionally a few 30") plus has another version in 21" with a wooden frame (which we are presently testing and likely offer in the future.)