I always use Extend, Heighten, and, less often, Empower on all my wizards. Extend for Haste, Animate Dead and Sense Vitals mostly, and Heightened Stinking Cloud is so good that it alone worth a feat, but adds a lot of freedom in spell slots management too.So does metamagic have any use for non-sorcerors? I'm trying to figure out if I should take this feat at all and it doesn't seem to have much usefulness or interaction with important spells at all?
For Cleric Heighten is less good, but can be useful on high levels for DC casters for CC on Chains of Light and Vinetrap. But Extend is must have for filling lvl 4 slots with Animate Dead and blanket buffing whole party with Death Ward when necessary. Melee clerics can also use it with Divine Power, Righteous Might and Divine Favor (+3 AB and Damage on first level spell!).
I avoid Maximize cause +3 spell lvl is too costly and rods are plenty. There is also Leviathan Robe from artisan for 6 free up to lvl 6 maximize.