I put together the W512 baseball subject set a year or so ago and I had SGC slab my collection. I originally purchased most of these raw or graded by PSA. One was already slabbed by SGC. I love SGC, but find it odd that out of this entire set, the one I bought that was already slabbed by SGC has a numerical grade. When I look at my set and see how some of the crisp cornered, great looking cards like my two Hornsbys have 'A', yet one of my Frisch cards has rounded corners and a miscut side get a numerical grade, it baffles me. I suppose I'll eventually send the Frisch back to receive an 'A' to be consistent.
When putting together the W512 set, I laughed to myself when I saw a few of them go for 3x to 4x more on eBay because PSA had a number on the slab versus 'A'. Most of the time, at least when I was putting together my set, the numerical ones didn't look nearly as good as the 'Authentics'. That experience clearly illustrated to me that far too many people are buying cards for grades rather than eye appeal.
For individual cards, I voted to have TPG slab as 'Authentic'. Now, I'll make one caveat to that. If there's a FULL, UNCUT sheet of strip cards and TPGs have a slab big enough for the large sheet (not partial strip!), I'd be fine with numerical grades. But since I don't believe TPGs have slabs that large and I see very few full, uncut sheets, I don't see that happening.
My W512 collection: