Why do people say it's easy to cap haste?
Looking at thf alone:
Wal-mart turban 5%
Raparee Harness 4%
Homam hands/legs/feet 9%
Swift Belt 4%
= 22%
Swap in Dusk +1 and velocious belt = 25%
That is the highest thf can possibly get (aside from using a ridiculously rare shield or situational gear like besieged/assault gear)
Dusk +1 and velocious/speed belt are NOT easy to get, nor is Homam.
Let's look at magic haste: According to wiki, this caps at 43.75% (how anyone can possibly confirm this is well beyond me)
rdm or whm haste = 15%
double march caps at 20% (40% with 2-hour)
So that's 35% magic haste without brd 2-hour, and that's ALL there is. The ONLY way to cap magic haste is with brd 2-hour AND haste, (I'm disincluding spy's drink since it's exlusive to salvage and besieged).
I'm going to also ignore ability haste since unless you're 75 drk it's still impossible to cap total haste unless you have hasso AND haste samba.
As much as I don't like to name call, anyone that says it's easy to cap haste is a *** retard. In fact, the only jobs that can even hit 25% haste in gear (in normal situations) aside from thf are MNK WHM DNC and BRD. Requiring Dusk +1 and speed/velocious belt to cap haste is a ridiculous thing to call easy. Brd 2-hour is the only way to cap magic haste. Only 75 DRK can cap JA haste, and is the only job that can cap total haste without BRD 2-hour.
So I repeat, anyone that says haste is easy to cap is a retard.
To the OP, haste is better than dual wield because dual wield lowers tp gain per hit and only works on melee attack speed, whereas haste will also work for spell recast (utsu for instance). So, stack on every piece of haste you can get your hands on, and if it's convenient to do so (ie. won't kill your accuracy), stack on dual wield gear everywhere you can't.