hello,

1.do you have a fixed budged for communications?
2.how big is your business(how many users of phones)?
3.the domain you are activating in and type of business partners(more national calls fixed/mobile or international calls or sms?)
4.how ofter you travel abroad and how often do you need to use your phone abroad?
5.do you have signal in the area you are activated(if not antenas can placed for signal after negotiation)

these are only some questions that you need to anwer yourself or in a meeting with a sales person before taking a decision.

hope it helped...