I believe that PMG is the most accurate of the two, I grade all my own currency but if for some reason I had or wanted to have something graded correctly PMG is where I would go.
I check a lot of different TPG
's just to see how close my grading is and it amazing how some of them grade.
Just for kicks check out the 1934 $1000 FRN post back on 1-18-2012, look close at the $ 20. note that was graded by PCGS, then ask yourself, would I pay VF price for a note like that, yes any TPG
can make a mistake, and PMG may have made some also but so far I haven't found any, I'm not saying they aren't out there but I haven't seen them.
I can show you a lot of PCGS notes that to my eye aren't even close to being graded correctly. And it seemes easy to fine them. Of course some PCGS notes seem to be ok, I guess it depends on who is doing the grading at the time.
The Bill Collector