can't beat sony quality
Crutchfield Customer Review (What's this?)
Aftermarket, third-party batteries are readily available and much cheaper that sony-branded product. However, "your mileage may vary" applies especially well to electronics like camera batteries. Aftermarket batteries we've tried, even those rated to have larger storage capacity, simply don't have the charge life or service life of the factory sony batteries. If they're half the money, but last half as long in service life or run down twice as fast... so did you really save money? We've been tempted by low cost, but the third-party products simply don't last as well for us plus the reality that their use could void a warranty. So, we've gone back to sony batteries in our sony equipment and are happy doing so.
Pros: factory built, factory recommended, factory performance. no surprises
Cons: up front cost is higher than third-party product, but safety and reliability are worth something.