I don't know, I'm very impressed with the Hyperion battery for my Galaxy Nexus. I had a Seidio battery for my Droid Incredible, and that was very spotty - you could definitely tell it didn't have the capacity Seidio claims it had. The Hyperion is much cheaper, and has vastly improved my battery life, so I'm happy.
Weird, every time ive tried a 'discount' battery off amazon its been total crap. I actually bought a Mugen for my old GSII and it was amazing, though the price was definitely high. Seido makes good batteries, but lacked NFC support which hte Mugen's had(in the case of the GSII where the antenna was in the battery). Wouldnt be surprised if that discount battery after a week has issues, like most do, and even the reviews show after a few charge cycles it performs extremely poorly.