Most of what I get from Japan is shipped via EMS. This seems to be a popular method and it has great tracking. I get things faster from Japan than I do from the west coast of the USA. I am in Maryland on the East Coast. The items have never been held up for me.
Do a quick search for EMS Japan for more info. Items come into the USA and quickly pass customs and then are delivered by the usps.
I likewise have bought camera equipment from Japan, and have never been charged duty. The last time I imported a lens, using EMS, I tracked the package, and it cleared U.S. customs overnight, so it was quick.
If you opt to use a private service like FedEx or UPS, it's possible you may get hit with a bill for customs duty. I imported some parts for my car last year, and FedEx promptly paid the duty, and later billed me for it. YMMV.
I bought an O45 off ebay from a seller in Japan. I wondered if I would get hit with a duty, but I didn't. I don't recall what service they used to ship the lens, I believe I received it in the U.S. Mail.