SD Card photo recovery - PC or Mac?

Friend of mine has accidentally deleted everything on the SD card in his camera. As he is not computer literate at all, I have volunteered to see what I can do.

I've previously had excellent results with file recovery s/w on a PC when I accidentally deleted a partition (oopsy) , but that was some time ago and I forget what the app was. Not tried on a Mac. As I have access to both to Mac (OSX) and PC (Win7) , any advice on which is likely to give best results or will either be equal?

Quite willing to pay (well, he is , so any recommendations for apps?

TIA

Answering my own question, Photorescue gets a lot of plaudits and works on both OS's so think I'll give that a go.

Just to close the loop, I used the free Photorec (on Win, though there is a Mac version) and payable ($30) Photorescue on OSX

Both recovered the same number of files*.

Photorescue was easier to use (GUI rather than old fashioned 'green screen') and basically nothing to do except start it and IMO is recommended for the non-computer savvy, it also recovered the original file names, which Photorec did not manage, renaming each file with a leading letter and numbers, none of which bore no resemblance to the original name. eg DSC000507.jpg might have ended up as f2223465.jpg. Both did however manage to get back the actual file dates and times which impressed me.

Photorec also recovered (or created?) a small thumbnail (started with t instead of f) for each file.

Both took about 20 minutes to recover 320 or so files on an 8Gb card.

* At least, Photorescue showed me the files it would have rescued had I paid for it, in trial mode it shows you the files that would be recoverable, a good feature as you dont have to pay until you are sure you can recover the files. I didnt actually run that last step though.