I use these 9 volt batteries to power some guitar effect pedals that may prove difficult to hum when connected to AC power.
The guitar effects are usually very energy intensive and the quality of the battery used really made the difference. The "More Power" Duracell make the difference in this type of use not only because they generally last longer but, above all, because they give a true 9v during a period longer than other batteries.
If we stick only to the overall length, one can say they are a bit too expensive but, as I précisais above, their ability to provide real 9v much longer is the asset mainly on brand batteries of major distributors.
