To me the flanger block on the III has a lot of great qualities and flexibility, my only wish is that the signal strength could be made stronger.
When I A/B it with the almighty MXR 117 or Ibanez FL301 it sounds sonicly close emulation-wise, just not as robust and defined as the pedals. To be clear, this only about strength of the effect signal in the mix, that's it.
When you engage an MXR 117, you know it, it just hits you. I don't get that with flanger block, it just seems a bit lackluster, sometimes I wonder if it's even on.
Again, the emulation aspect is pretty much dead on, I just wish I could bring it up in the mix (yes, obviously I have adjusted mix parameter).
I have a similar experience with the phaser block too, sounds incredible, just wish I could make it hotter in the mix.
Bottomline... while, I will agree with M@ that Flanger on the Axe-Fx III is the best and most flexible flanger you will find... I just wish there was more of it to be had in the mix. =:·)
Just IMHO