Kozuka is correct. This is the best mainhand for THF at 50, and arguably still is up to 60-ish.
Emrod's TP comments aren't accurate, however. When Dual Wielded, the TP return of 2 Corsair's knives still requires 3 Store TP to retain 5 per hit. This and a 180-delay require 5 (A Rajas ring). A Hornetneedle will require 7...which is currently impossible until level 60. By then, better combinations start to appear anyway.
I'm not sure why you guys are talking about this weapon and its tp, and retaining 5 per hit, tp is stored to one decimal, so its not like you are earning 4 tp if you arent earing 5. i would take this weapon for its dps...
These used to be 200k when I bought mine. Now its hard to get 50k for em. People should be beaten for letting the price slip from 90k to 45k in 3 weeks. I hate FF's economy.