We're using it and we like it. I created some feats that allow faster recharging should the players want them. ..in fact, here they are:
Rapid Recharge [Metamagic]
Your spell energy recharges faster than normal.
Prerequisite: Spellcaster level 3+
Benefit: Spells with a General Recharge Time (see table 5–6, p158 UA), may be cast as if they were two levels lower. No spell may have a recharge time more frequent than every round.
Example: A 6th level sorcerer normally casts 3rd level general recharge spells at an interval of 1d4+1 rounds, 2nd level at 1d4+1 rounds, and 1st level at 1d4 rounds. With Rapid Recharge, he can cast 3rd level spells at an interval of 1d4 rounds, 2nd level at 1d4 rounds, and 1st level at 1d3 rounds (two steps lower on the chart).
You may take this feat more than once, but each additional time only decreases the level by one more step.
Spell Expert [Metamagic]
You can cast specific spells with very little time and effort.
Prerequisite: Spell Focus, key ability 13+
Benefit: A spellcaster may select a number of general recharge spells he knows equal to the modifier of her key spellcasting ability (Charisma for bards and sorcerers; Wisdom for clerics, paladins, and rangers). She may cast these spells as if they had the standard general recharge time minus her key ability modifier (Charisma or Wisdom). For specific recharge spells, the time is divided by a factor equal to 1+ the caster’s ability modifier (Charisma or Wisdom). General recharge spells can not be reduced to a recharge time below 0.
Example: A 6th level sorcerer with a Charisma of 15 may choose two spells to use with her Spell Expert feat. She chooses fireball and charm person. Her fireball has a new recharge time of 1d4–1, and her charm person spell has a specific recharge time of 20 minutes (1 hour/3).
The effects of Spell Expert do stack with the benefits of Rapid Recharge.