I've had one client setup on their service, and it worked well. Unfortunatly, it worked well for a hacker who got in to their network through gotomypc.com. Seems their authentication isn't as secure as it should be for an internet/web-based VNC option.
For direct connections, I've had a better time and feel more comfortable with Symantec/Norton's pcAnywhere, and even more so with Microsoft Terminal Server and Citrix Metaframe.