To those thinking that they help by sending people to perform google searches (if you think that at all), you should understand that many people land on this forum exactly by searching google for relevant information. That was my case for instance, although I was previously a member here.
If you do know something, if you do have an experience relevant to the question, then share. If not, you know that one: silence is golden!
Between some useless posts I did find out on this thread that there are some other fairly reliably unlocking solutions besides the Gevey ultra S offered by applenberry. They are also significantly cheaper. This is the kind of information this forum is useful for. I might actually buy a GPP interposer on eBay based on the info found here.
I am still curious though about the experience others have with these unlocks, be it for iPhone 4S or for older models.
One question I would have is if you generally have to buy yet an other interposer if you want to upgrade to the next major iOS release (in this case iOS 6 I suppose).
My guess is that the answer to my question would be yes, but maybe you can share your experience, like if you maybe kept an older version of iOS just to maintain your unlock or if you bought an other interposer (gevey, turbo, GPP... whatever it's called) just to be able to upgrade to the next iOS.
I noticed for instance on eBay that the GPP for iOS 5.1 is different than the one that works for up to 5.0.1 and it costs roughly double ($20 vs $10).
Sumit76, your experience is not encouraging for instance. Data not working makes the iPhone and the unlock a bit useless. I would not bother to unlock if I knew that the data will not work overseas.