Personally, I think this mostly makes a great dip. Two levels gives you Silent and Still on every spell and removes limits on effects based on caster level. The third level is a bit more debatable since you're missing out on three levels of spellcasting advancement, but a Wizard or Cleric would still be able to get 9th-level spellcasting... and then be able to apply Maximize, Persist, or Quicken for free seven or more times a day.