There are lots of reports of SD cards (particularly larger SDHC cards) not mounting at all in the internal reader, or mounting only some of the time. Some said their reader stopped working after upgrading to a new version of OS X (Lion or Mountain Lion). A few Google searches turned up loads of threads about these problems.
I don't think these complaints were exclusive to 2011 MBPs, but the majority of them seemed to be regarding those. I did read
the Anandtech article, which I believe is what alerted me to these issues to begin with.
chrfr and NewishMacGuy, do you both have the 2012 non-Retina MBP?
Does anyone know whether or not the reader in the 2011 non-Retina MBPs is the exact same hardware as in the 2011 models?