First of all, both are excellent power supplies. Ironically, the corsair has better specs, even thought the overall watt rating is slightly lower. This makes me question Thermaltakes rating schema.
Thermaltake: +3.3V@25A, +5V@25A, +12V1@55A, +12V2@75A, -12V@0.8A, +5VSB@4A
Corsair: +3.3V@30A, +5V@30A, +12V1@100.4A, -12V@0.8A, +5VSB@3.5A
Both are fully modular, both are gold certified and both are rated to last over 100000 hours. The corsair has better tolerances (but not a great deal better) and is $30 cheaper. Other than that I don’t see a big difference.