I'm not a miner, so correct me if I'm wrong, but that seems like a bit of an apples-to-oranges comparison. Tesla cards (and the servers designed around them) are intended for specific use cases: mission-critical enterprise solutions and scientific HPC. As a result, they run slower processor and memory speeds in comparison to nVidia's own consumer products, use ECC memory, and are optimized for double-precision over single-precision performance. Mining with a Tesla is like gaming with a Quadro card.
There is nothing mission critical or 'enterprise' about Tesla/Fermi cards. You can crash them and lock up your whole machine. Even if you can reboot the OS the card may not respond and the rebooted OS won't see it, we sometimes have to physically shut the machine down to reset the Nvidia card. Nvidia is still a gaming company at heart and it's going to take a while for them to adjust to providing equipment that is meant to be reliable and not just fast.
