It looks like a nice bike, however, Tern is owned by folks who left Dahon (although there is speculation they both are jointly owned -- do a search). It is therefore likely that some parts on Terns will be proprietary. If Tern behaves like Dahon, which they claim will not be the case, then component specifications may change almost yearly. Folks who own Dahon bikes often claim obtaining replacement parts is difficult or impossible.
Bike Friday uses standard components so if something breaks one does not have to request proprietary replacement parts. Some used Bike Fridays for prices that may be similar to the Tern can be found here:
http://www.bikefriday.com/bicycles/pre-loved