Opteka OP-512 battery (BP-511 equivalent)

I know there are many threads and posts on the Opteka grips, but I am wondering about the Opteka batteries. In particular, has anyone purchased and utilized the Opteka OP-512 (equivalent for Canon BP-511, BP-511A, and BP-512)? If so, please share your experience with this battery and, if applicable, let me know where it stands in comparison to Canon and/or Sterlingtek equivalents (reliability, performance, fitting, etc.).

I am considering Opteka as a less expensive alternative to Canon instead of Sterlingtek because of the fitting issues related to Sterlingtek. The batteries are intended to be used in a Canon BG-E2N grip (yes, I caved... :rolleyes for my 40D.

Here is the product description from Opteka's own web site: http://www.opteka.com …Action=VIEWPROD​&ProdID=56

Thank you!

AFAIK, Sterlingtek had a bad batch, which they replaced; there's no systemic problem with their BP-511s. I certainly haven't had any problem with mine. And I wouldn't expect that Opteka's going to be immune to an occasional bad batch either. But you can be the guinea pig for us :{)#

I've sold hundreds of Sterlingtek batteries over the past few months and not had a single fitment issue (touch wood). The issues were resolved with the manufacturers a while ago.