Hi, Anyone have any input on the quality of Camcorder batteries from alternate sources. Specifically Equivalents to Sony NP-FM50, NPQM -71D, MPQM-91D, how good are those from alternate suppliers? Do they last as long? (In use time and or Life) Do you get what you pay for. Glad of any experiences as I need to purchase several and as they are not an inconsiderable amount of my "Pocket Money" I would like to buy wisely if possible.