If you have a phone that works in a foreign market you're going to pay a ton for worldwide coverage anyway. It's cheaper to just rent a foreign phone where ever you're going.
The advantage of a GSM world phone is if you have it unlocked (meaning it will accept any carrier's sim card) you can use your own phone and just pop in a new sim card. This can be even cheaper than renting a foreign phone is the way I understand it.
But like I said before, I work for Sprint so my opinion is biased towards CDMA even though those handsets are locked. And when comparing Verizon to Sprint, what Cardnial185 said is correct. Verizon buys a considerable amount of fiber bandwith from Sprint. I know this because I work in wireline billing and they are one of our largest customers.
If any of you decide you want to switch to Sprint check this site out:
http://www.sprint.com/sero You need an employee's email to access it (
bradley.x.robertson@sprint.com) and it gives you discounts you can't find anywhere else. These are the cheapest Sprint rates available to non-family members.
EDIT: Just to clarify the first post the Instinct is not 4G. There is no such thing yet. You could maybe call it 3.5G since it is EVDO Rev A, but the 4G designation on Sprint is reserved for phones with ZOHM (wi-max) capabilities.