Without any doubt the most impressive characteristic of the Thortech Thunderbolt Plus 800 W is the iPower Meter. With this little device, which mounts in a 5.25" bay, you can be informed in real time about the watts, amps, voltages and efficiency of the PSU. You can also set the fan to work either in auto or in full mode (not recommended if you can't stand high noise levels). The power and current per rail you see on the iPower Meter are very close to the real values, however its voltage and efficiency readings were far from accurate. Also the fact that the iPower Meter can be only mounted in a 5.25" bay isn't so ergonomic, since if you have your PC installed under the desk you have to bend to check the readings.
I was quite satisfied by voltage regulation at +12V and 5V but 3.3V was a bit loose, but still within 5% deviation. Also I would like to see higher efficiency, especially at full load where even though we use 220 V, I saw under 87% efficiency, the 80 Plus Gold threshold with 115V. Finally ripple suppression was quite good and the performance in Advanced Transient Response tests was impeccable.

Bottom line, if you find the iPower Meter an interesting gadget then this PSU is definitely worth its cost since it has enough capacity and connectors to power two strong VGAs, is backed up by five years of warranty, efficiency with typical loads (40-60%) is over 90% and transient loads won't pose any problems. If the iPower Meter could be installed on the desk or even better if some software was provided then its usability would increase a lot.