Performance -
As with any battery what you want to know is performance. Before running our testing we ran a base line with the stock battery and also refreshed it. To do this we drained the battery completely and full charged it three times. From there we used the battery for the next 5 days under normal usage and timed how long it took from full charge to dead phone on multiple runs (including standby time). This gave us an average battery life for the 1730 mAh battery at roughly 16.4 hours. This is not bad really, but still very shy of the 30-36 hours we have seen on some iPhones.

We performed the same refresh on the Ontrion battery prior to testing it for the same 5-day period. We were very impressed as our average life cycle was 32 hours from full charge to dead phone. We wanted to be sure of this and continued the testing for another 5 days. The extra time we took to test did give us a more accurate figure of 30.2 hours from full charge to dead battery. This is very impressive as we did use the 3D Camera and even captured some 3D video footage during both tests. Our high time with the Ontrion 2300mAh battery was just over 36 hours and our low time was 28 for the ten day run(one of the times when we shot a lot of 3D stills and video).

Now for the downside; the 3D Camera on the EVO 3D is not the best in low light and already has some focusing issues. These problems were further complicated when we were using the Ontrion cover that comes with the battery. The depth of depression the two lenses sit in block out ambient light which the camera really needs, but it is not enough to force the flash to snap. We found that we also saw more focus shifting when using the included case. Now, if you do not use the camera much that is no problem; but why buy a 3D phone if you are not going to use the 3D Camera.  

We also had problems with the vacuum sealed DryCASE, because the plastic film was not able to seal against the camera lens we were not able to use it at all. The distance between the lenses and the cover caused the camera to continually attempt to focus (on the case and not the object) we also noted that the air that was left there fogged very quickly. Of course you may never use a DryCASE with your phone, but it is something that you should still consider if you are thinking of getting this battery for your own EVO 3D. Ironically the added depth to the phone makes using the camera easier as there is more to grip when using the shutter button on the side.