I'm much more inclined to buy from a 15-person company like them than from a 15thousand person company, really.
Devon IT is also a small operation and ThinKiosk is, apparently, one person. All seem to be doing their job well and I don't see more risk when working with them than with anybody else. Being big alone does not imply financially sound, and vice-versa being small does not mean unsolid. Also - There are just so many examples were users got p... off because big companies killed something they used or the big company disappeared (remember neoware or Compaq?)
But that's something everybody must decide on their own, isn't it?