Yeah, people who have updated their early 2011 models with an SSD and 16GB RAM only this year sound very happy.
Geekbench scores for single Core are similar to my 2010 quad core iMac i7 and roughly double the White MacBook.
Understandably, the iMac doubles it on MultiCore score.
Planning on adding a 1TB SSD, 16GB RAM and replacing the cd drive with a 2TB disc drive for all my GoPro footage.
I'll then simply have one 4TB desktop drive for Time Machine and use Amazon Drive for image backups, so that's a lot of storage and backups in just one 13" machine and one dictionary-sized hard drive.
Confident it'll handle my music production requirements. My main concern is video editing, but I think using ProRes it should be Ok.. will probably just take ages to render!