Battery for Rowland 8Ti

Is it worthwhile to add a battery to a Rowland 8Ti?

How long is the battery usually last?
You can probably find the information right on Rowland's website( There's a specific discussion about the battery power supplies. I kind of asked the same question to Rich Maez, JRDG's Technical Services Director, and he implied that the worth of the battery power supply was relative to the quality of the AC mains power where you live.
After owning different Rowland gear Ucmgr is correct. If you have good AC than you will not notice great improvment. If you have bad AC it can be magical. I have used the battery on Rowland amps and preamps.