I've been there to browse out of curiosity, but never used them, but have heard that they have fairly reasonable (though usually not the best) prices, seem to offer good return terms (except software - but I know of VERY few that will do that even for a legitimate mistake unless the product is proven defective), and have above-average customer service (for that kind of place). I wasn't aware they were USA-only. I assumed they would ship anywhere if you were willing to pay the costs (which would probably be outrageous and negate any product price benefits of using them) - but I never checked.
Then again, I used to buy my cigarettes from the Ukraine because a carton was $12.95 in the quantity I purchased - but shipping added about $5 to EACH carton with no quantity discounts (and I was buying 24-36 at a time). Despite that, the overall cost was about half of what it cost locally, so it was still a very good deal. Thank heavens that's one vice that's gone for good.
I'm a bit surprised as it seems like it's not much effort to expand shipping (and the customer pays for most of it) and appears on the surface like it would increase sales quite substantially (though I suppose it would require some additional banking efforts to deal with foreign currency rates and transferring funds, foreign language versions of the website unless they decide to just go with English and ignore the others, setting up international phone numbers whatever that takes, dealing with international laws and tariffs and rules about the transfer of certain goods or technology, and probably more than I first considered when I said it seemed rather simple).
I buy all my computers direct from Dell. I'm too impulsive with other smaller purchases to wait for the mail, so I normally get them at the local Micro Direct store (even if it is a bit more expensive and I have to deal with travelling to do it - not as easy these days as it was in my youth or even just 2 years ago). Other electronics I buy (like audio or video equipment) - which is VERY rare as I always buy the second best after thoroughly researching the choices so they last a long time - are generally too high-end for this store to carry. I get the very rare audio or video from Amazon.
I don't have any game devices (other than the computer I suppose and some old board games including my treasured and valuable marble Chess set) and never buy games (the last was the original Doom which I'd bet many of you never even saw as it was before your time) - otherwise if in that very rare mood, I go online and play Chess (I was once rated highly and I'm still pretty good even though nowhere near where I was in my teens), Pente, Go, Hearts, Spades, or Oh Pshaw. I've tried some of the new games like WOW and Halo when visiting friends with game systems (though I did go through the 30-day online WOW trial) and I just don't enjoy them (possibly because I tend to get killed almost immediately with every one I've attempted - LOL!).
Sorry I can't help more or give any first-hand experiences, but for what it's worth, they are a fairly large company, they seem to be here to stay, and I'd consider them trustworthy if I found myself in a position where, after checking things out, buying something from them seemed the thing to do. It's not a scam where they take your money and disappear.
But from other feedback, it seems that this only applies in the USA (due to excessive shipping costs). And as mentioned before, the basic pricing is not the best (you can almost assuredly do better with a little more searching unless you happen to catch a very special sale on exactly what you want), so the chances I would ever use them are rather slim.
Good luck!