As a main weapon Mat bow > Great Bow. Mat has higher avg dmg, +3bow skills and Great has 121str req.
First of all you have to decide - runner with Forti or tele with Enigma.
Some people can't accept that telebowa is way faster. Runner is the best if you like to wait for tp on Baal runs

Ofc both of them can give you a lot of fun.
GMB needs 95ias with 13+fana to hit 7fpa. If you don't want to sacrifice Forti or Eni then basically you have to wear 20ias gloves, 20ias ammy (Cateye/HighLord), 10ias belt (Nos) and 3os Tiara 45ias.
GMB don't let you put reasonable fcr on you gear. So probably you will not see telebowa with GMB.
Shadow/Diamond/Mat are your choice for tele. All of them are really close and all of them allow you to hit 68fcr breakpoint with 7fpa. Mat gives you marginally less dmg but you will get +2 to zon skills which increase all your p&m tree and is valuable if you play hybrid zon.
Depends of Fana lvl, Shadow/Diamond need 65/70ias and Mat 45/50.
In case of classic bowa, probably GMB is bis. Shadow/Diamond/Mat can be an option if you play hybrid or want to keep more flexibility (free belt slot). About Piercing, GMB only rely on skill level. You can't wear Razor. Also bis 3os 30frw tiara is really expensive.
There is also 3rd option for both types of zon, probably the best one. Windforce and Faith merc.
With shael'ed WF you need 60 gear IAS with 12fana or 55 gear ias with 13+fana.
Great option can be also Mist GMB with Faith Merc. I'll test it soon. Mist gives you a lot of gooods, especially 100%pierce and 40@res.
Edit: and Blizz has capped bow speed to 7fpa. Not remember when, probably since 2.3.
This post was edited by gratek on May 17 2022 02:18pm