Another NZ user here. Again, not much hopde of warranty if something goes wrong, and the Sony store is next to useless. Other than that I haven't had any problems.
As far as content goes, if you can get it from Sony, it can be got from Fictionwise/BoB. Might be a bit more expensive then sony store but buying from FW/BoB means I can (usually) strip DRM and format the books how I like for the sony reader (embedded fonts etc).
And the prices are STILL usually cheaper than what I have to pay for the exact same book in a NZ bookstore (if they even have said book in the first place - bloody whitcoulls and co.
)