Have not bought the "Digibuddy for Can NB-5L" on Amazon, but have been pleasantly surprised by the battery capacity. I have the Digibuddy initially charged twice with the Canon charger, discharged by continuous operation in the Canon SX220HS again and then made video recordings at the brightest display setting for the third charge. The original CANON NB-5L battery was about four to five times fully charged since the new acquisition with the digicam. Again, were made with the brightest display setting video recordings.
Result: The recorded up was at the Digibuddy about 20% longer than the original Canon battery.