-They will take major American credit cards.
-They always charge actual retail price with no markup (if anything, minus a bit).
-They charge for shipping AT COST (meaning they will not gouge you or charge you importing fees... the price you pay for shipping is what it actually costs to ship).
-EVERYTHING you buy there (with the exception of the marketplace sellers) is guaranteed to be legit and NEW. All your money goes directly to the folks who made it... not idjits who are reselling 3rd hand stuff to you for 100% markup.
-they have virtually everything currently in print in Japan (I've never NOT been able to find something there... ocaisionally it's out of print... but the listing still exists and will tell you as much in those cases).
It's the only site I recommend to people looking to import things from Japan... since most other legit sites won't deal internationally and most of those who will are total crooks looking to exploit people who don't know any better.
The only disadvantage is that very little of the site is in English (though all of the order forms and search categories can be seen in translation)