If I were a business (which I am, IT services for the SMB market) I would not want production IPv6 traffic using a tunnel for that traffic. Especially if I were selling services to clients that relied on that connection.
Your connection is subject to one more company keeping things working, and since tunnels are essentially transition and demonstration technologies I expect them to go away. Plus, your regular ISP can shut them down at any time by blocking the traffic. In HE's situation blocking Protocol 41 would be sufficient. In addition there are additional complexities related to setting up and maintaining a tunnel that are not present with native IPv6 that all to often break with things such as power outages or even IP address changes if you don't have a static IPv4 address.
Of course that depend on you being able to get native IPv6 connectivity from an ISP.
That said HE's tunnelbroker is great for a business that wants to experiment with and test IPv6 before rolling it out, and for home users that don't have some of the needs (including uptime and reliability) that a business has. I use it for that for myself and my business, but unless a client has an absolute requirement for IPv6 I won't roll out a tunnel for them, I'll just wait for native IPv6 and security tools that provide the same coverage as they do in IPv4.