FWIW, I bought a 450 fairly recently from the US (I live in NZ) - had no problems whatsoever, found it very easy to get free local maps (autorouting and topo) - and not illegal copies, but third party free (open) maps. I'm very happy with my purchase - got a mount for my motorcycle (made by RAM Mounts) at the same time - so I now have a waterproof GPS for te bike as well a a geocaching tool.
For me it was standing in a field in the dark and rain, with my Blackberry getting far to wet that pushed my into making the right decision. Officially imported units in NZ are way more expensive than those available in the US - including shipping costs - so go for it!