I've had the Hyperion battery for about 3 weeks and I wasnt too impressed with the first 10% dropping off after charging in a span of two hours. I raised serious concern about it and Hyperion refunded my money and told me to keep the battery. I am waiting for my Anker to be shipped to me sometiime this weekend. I hope I have a better experience with that one.
As for the OD mod for the extended battery, I strongly suggest to do it if you have a dremel! I didnt have one and it took a lot of work to cut through the Otterbox case...Whew! Other than that,I love it!
So basically you two don't like the hyperion batteries? I'm asking because I'm in the market for an extended battery and wanted to get either the Hyperion or Anker. From the looks of things I'm leaning more towards the Anker. I've had the Hyperion on the S3 and it was awesome lasted long and I remember reading something about our wall chargers only let the batteries for so long so it doesn't charge the extended battery to its full potential. So I would always put in my OEM battery while I charge the extended on its own charger.