All of my batteries, except the one that came with the camera are third party. They work better than the OEM and cost half the price. You are paying for a brand logo with an OEM part. I have never had an issue with a third party battery, and I've never heard of anyone having any problems with a third party battery. It's your money, spend it how you want, but remember, the manufacturer has a reason for wanting to scare you into buying OEM parts. It's called, markup.
Yes, you do pay some for the Name, you also pay some to maintain your warranty, provide support if something happens, etc. For me, I stick with OEMs for my batts.
Never heard of a problem with aftermarket batteries? My primary job is in IT. We routinely have issues with cheap aftermarket batteries, at least a couple a month leak, bulge, die prematurely, etc. While we have OEM batteries that do the same, we have 100 times the OEM batteries come through our shop (since they are shipped with every laptop from the factory that way) and have 1/100th the problems from the OEM ones.
Believe what you want, and I wish you the best of luck with your batts, but I will stick with the OEM thank you.
Allan