Our company implemented a ThousandEyes solution back over the summer.
We're a cellular SP and we were having issues with slowdowns/packet loss on our customer network that we couldn't explain. We implemented enterprise agents on small workstations attached to cellular modems and used ThousandEyes to monitor that connectivity. Setup was quick and painless.
We also implemented a few VM enterprise agents in our core network and some endpoint agents in our retail stores to monitor their connectivity back to the corporate office.
We love the BGP monitoring it provides us and plan to rely on it extensively during a core network migration when we'll be switching our eBGP advertisements to new providers, a few networks at a time.