You should be clear to buy a 530 by now (at least as far as button problems go). They fixed that after the first few weeks of production I think.
As for other bugs, well, it's Garmin. I just received a warranty 530 because my original one won't stop disconnecting randomly from my phone. We'll see if the new one is better.
You would need to load the correct maps if you bought from out of country, but it's simple to do. DC Rainmaker has instructions.