By all means if you can afford it.
It is fantastic!!!
Remember that the plans are expensive. it is not just the phone that you pay a lot up front. The monthly service fee and then, some more.
However, if you travel overseas you can have it unlocked (by a different company) and just buy a SIM card wherever you go and you get to have a very inexpensive cell phone overseas.
It pays off because AT&T overseas plans are extremely expensive and they are not worth it. You get better reception overseas with a local phone company.
If you want to have another phone with a U.S. line for people to call you when you are overseas, google: http://www.maxroam.com/