Let's see... infinite recources AC, ignoring anything both could have in equal measure (Ioun Stones, Amulets of Natural Armor, Rings of Protection, size small + Reduce Person, and so on).
+5 Mithral Fullplate, +5 Animated Tower Shield, +3 Dex: +26 (or +5 Mithral Fullplate, +3 Dex 16, +5 Animated Heavy Shield: +24)
Monk's Belt, Wis 32 (16 base, +5 level up, +5 Tome, +6 Peripat), Dex 26 (16 base, +4 Tome, +6 Gauntlets), +8 Bracers of Armor: +28.
Now, if you're pushing your Dex and Wisdom that much anyway, the Monk's belt is better, hands down. If for whatever reason you can't use good armor or shield (an Arcanist or a Druid), again, the Monk's Belt is very useful. Epic, the Monk's belt becomes exceedingly useful. For just about everyone else? Mithral Fullplate and an Animated Shield will win out.