I have a number of slabbed notes listed and recently I sent some notes from my own collection for a PMG grading. To be frank, I have done this to see how my grading compares with what comes back from PMG. Grading is key to the value of a note and for sure, I never over-grade any note. I can see how some buyers like the guarantee of a slabbed banknote and I know one collector who only buys PMG notes and then cuts open the seal and places the note in his album as he likes the ‘feel’ of the banknotes. But he has the grading  assured. For me, the jury is out. I know Auction Houses must like the slabbed notes as they are selling a defined grade but still, I trust my own grading as well as respecting those who prefer the PMG notes.