Hello Jeroen,
Very good hint. I've always been trying to measure performance to deutsche telekom but they don't really offer test-locations. With the TTM-boxes one can do that. We have just ordered ours and it should be operational within the next 4 weeks. The TTM-project is a really good tool for network operators. Especially with latency crtical applications like VoIP or gaming the ttm-boxes are the last option you have for troubleshooting.
Regards, Gunther