+40 stats is always nice, though you have to compensate your stats for the attack speed you lose (10 aspd, +10 agi fset bonus =! 40 agi, most of the time), and the freeze protection that an F.set gives. That may mean giving up an armor slot for Marc/Detale (replacing either a Tao, or your GR, w/e) which, would not be very good against many characters trying to kill you, i.e. WoE/GvG. You save alot of stat points on DEX and other stats, depending on the build, which may make up for the higher AGI you need to add.
Of course, it will all depend on the environment you'll fight in.