In all the time I’ve played 3e, I’ve seen numerous metamagic feats used that increase the effect of the spells they are applied to. Empower, Widen, Extend, Quicken, Heighten (though IMC all casters get this one free)… but I’ve never seen Silent Spell or Still Spell used.
This suggests to me that these two feats are perhaps underpowered for their cost. I am considering replacing both feats with the following:
Subtle Spell [Metamagic]
Benefit: Applying this metamagic feat to a spell removes the need for one of the Verbal or Somatic components, decided at the time of casting. This increases the level of spell slot needed to cast the spell by one level.
Special: This feat cannot remove the verbal component of a bard spell.
Improved Subtle Spell [Metamagic]
Benefit: Applying this metamagic feat to a spell removes the need for both Verbal and Somatic components. This increases the level of the spell slot needed to cast the spell by one level.
Special: This feat cannot remove the verbal component of a bard spell.