When you go "Factura" you're getting into a contract and they want to make sure you are a resident. Even if you own your own unlocked phones.
With Personal (back in 2007) not only they wanted our DNI, they wanted to make sure we had 12 months of remaning active residency the day we signed the contract. We came back a later date and they didn't check for the 12 months, but did take our DNI info and photocopies.
This year we dropped Personal and went shopping with Claro and Movistar. Both required DNI and ALSO required us to have a credit record (Equifax Argentina, aka "
Veraz"). If you don't have a Veraz report they can decline to sign you up. They check your credit report and make photocopies of the DNI when singin up. We ended up going with Claro (big, BIG mistake, but that's a different story). Depending on the services you contract and the type of phone you have/get, they may also require you to have a local bank account and sign up for direct debit as well (which you cannot disable until the contract is over).
The rates under a contract are better than pay as you go rates. You can also do international plans more easily and data plans. The biggest problem we had with Personal was that if you went over the limit specified in your contract (by even a few cents) they will shut off your line until the next cycle kicked in (could be days or weeks), or until you went and paid in person at their office. A simple international SMS could put you over the limit, even if you had $0 usage in calls. We had to go to the Personal office many times to pay overages of less a couple of pesos to unlock the line. As far as Claro, they are better in this regard but we have bigger issues with them now.
In summary, I would not recommend a contract UNLESS you definately need a service that pre-paid does not offer, or you can limit your calls and usage strickly to their plan terms. Otherwise you might get into overages and locked lines which can be a pain to deal with. Believe me, its worth paying the higher pre-paid calling fees than wasting hours dealing with the problems of a contract and the incompetent customer service these local cell phone companies have.
These were our experiences and yours might be differen depending when/where you inquire and signup. Good luck.
