Are Offsites worth the money?

As every leader knows, building a cohesive team and company culture is a key ingredient for any successful business. I read this article over the weekend - whilst we are planning for our next offsite. 

Offsite meetings where the employer pays for all expenses and employees engage in team - building activities (or even go surfing or skiing) have been pretty popular - especially in the VC and Start Up scene.  

The types of events are as diverse as the cost - and range from a simple dinner to lavish, multi day overseas trips. 

In my opinion, they are worth their money of you know what you want to get out of it and have a well thought through agenda is structures but also leaves enough room for informal, personal and spontaneous interaction between individuals.

I would be interested in peoples` experience with and opinion on offsites!