I gather PMG's grading is often too generous. What about the other firms? Are any of them more trustworthy?
PMG has tightened up over the past 6 months. However I think they are still hit and miss, most noticeably in the Unc 64 grades. Flicks, corner folds aren't uncommon but much less so now. In Unc's is where they can really miss-the note above a year ago would've probably made Unc. In circ grades they are odd. You'll see a note certified "EF EPQ" with a big stain on the back and no comment.
However as they have the full tilt support of one of the better known paper money dealers in Canada, they seem to be the flavour of choice.
For accurate grades CCGS out of Calgary is probably the best but his unc 63 is usually a PMG64/65 and his 64's a 65/66 and with the new cat categories, interperetation of his Unc 63's will be as C Unc as opposed to G Unc which then drives people to PMG
He grades them too hard in my opinion so PMG is getting all the biz.
No other service is worth crap