I smell a rat. I highly doubt that Apple or AT&T would let third parties unlock iPhones.

Also, this company doesn't seem to know the GSM standard for retrieving IMEIs is just to dial *#06#.

They will probably say that 'factory unlock for iPhone 4s' means it will work for all international sim accounts but the USA domestic remains locked.

Booooo on them for the play on words...

It's definitely not an "official" unlock by any stretch-- the official word is, AT&T and Apple have an agreement to keep my phone locked, period. :-)

I'm suspicious of ANYTHING that isn't official, only because I don't want to jailbreak my phone or otherwise screw it up. My phone is my life and I run my businesses from it... I can't mess around with beta/hack software, and when new iOS versions are released, I want to be able to upgrade, not wait a few weeks/months until the jailbreaks catch up. (Plus if anything goes wrong with my phone, I want to be able to take it to my local Apple Store without anyone looking at it funny and saying "oh, it's jailbroken, you voided the warranty" and that's that.)

I get the appeal of a jailbreak or unsanctioned unlock (I used to be the guy that ran bleeding-edge beta software) but it's just not for me anymore. That's why the Gevey is so appealing: it does the job but (in theory) can be popped out and my phone returns 100% to normal.

They do unlock just like factory unlock and I have used it with sim card from Hong Kong, Japan and other countries.
No jailbreak needed and when you do IMEI check , it does report it back as unlocked.
There are other online services that does this, you may want to check this thread http://modmyi.com/forums/unlocking-activation/811499-unlocking-my-iphone-t-question.html

This technique has been around for a while. I suspect that someone is bribing someone somewhere, but I have no proof of it.