Hey, Deadpool790, you might get better quality answers if you could give a clue whereabouts on planet Earth you live - it's a big place, and tax rates and rules vary.
I've used DigitalRev in the past - they are pretty good - based in Hong Kong.
I've also used B+H, who were also very professional, in Manhattan of course.
But whether you pay tax and import duty or not will depend a great deal on where you live. I ended up paying tax and import duty from B+H, but not from DigitalRev. I'm in the UK, and customs are getting very good at hitting you for tax on imports.
However, I've come to the conclusion with the 5D3 that I will buy locally, even if I have to pay a bit more. This is because with all the recalls and suchlike, I don't really want to have to return the thing by post across the planet, and then wait ages for its return, assuming that this is necessary at any point. Of course, if the savings were larger, I might be persuaded to go elsewhere...