Is this to access your corporate computer system from home or is it to provied remote support functionality to your clients through firewalls ?
If its the latter then i wouldn't recommend Webex due to the expense of having to purchase it on an as needed basis (i.e. pay for so many hours and then have to pay again) [Just my personal view]. There is only one other box on the market that i know of, that you actually own yourself and manage the hardware internally so you don't even have to go out to the internet (works through https so it traverse's internal firewalls easily).
If anyone is interested in this for providing simple, cost effective remote support for their working environment i strongle suggest checking this out, we use it at work and its fantastic.