I have enabled and used ipv6 on a number of machines, I did have this website enabled at one stage but due to the ipv6 pop being down for several months now, I deleted the AAA record from my DNS . I have my account and all my ipv6 tunnels with SIXXS using Heanet and OCCAID Inc. I never had a problem with Heanet so far, but occaid reliability has left me wondering if ipv6 at its basic level (tunneling) is ever going to get better. I have had to apply for two tunnels so far as occaid first pop that I chose has being Offline now for 8+ months now and their second pop is off line for at least 4+months with no fix time allocated. I could switch ipv6 broker again 
There is a big push in the networking community to get ipv6 up and running and to get as many users using ipv6 but what happens when a pop goes down and all the feed back that is given is: tunnel broker has been notified. Sorry for seem sarcastic but Wow that useful information, a fix date would be better! Also I have noted before, asking such question to sixxs support people get rude or not very informative replies.
I do know that sixxs are offering a free service and they do rely on the pop ISP to make the service avaialble, I suppose when you have to go through the process of applying for a new tunnel changing ipv6 DNS records, changing the tunnel information in /etc/network/interfaces. It can be a Inconvenience and frustrating experience.
I will as of today apply for my third tunnel through another broker in the US. Sigh!
You might want to try Hurricane Electric.
I’l note that native IPv6 connectivity is generally much better to tunnels. Please don’t judge IPv6 by the performance of one tunnel broker.
I suppose it wasn’t my intention to judge IPV6 solely on Tunnels,I was just pissed off that there was not fix time given and the only solution was to either wait or change tunnel endpoint.