I have 8s that I have NO idea how they're 8s and I have 9.5s (SGC) or 9s with a clear issue. Honestly, I don't buy into grading at all from a merit sense. A service like TAG, which does account for their work and give clear notes to their grades, is an absolute step forward but the sports card market has no meaningful interest at entertaining new grading companies and it's a real crappy "chicken and egg" thing. Most of the time you're going to grade a card to try and increase its value...the service that increases its value is also one of the least transparent companies out there...so you either choose a better or at least more accountable service and take a notable loss on any future value or...you give in. For me personally, the main value of a PSA is authenticity, so I'll only buy PSA or SGC for cards that have a lot of fakes or good reprints flying around (largely vintage) and pretty much never pay a huge premium for grade.
Like for instance, let's take two of one of the more "defining" 2020s Topps baseball cards, the 2022 Julio Rodriguez Update RC. Let's say you wanted a primo copy of this .
This is a
PSA10 sold for $22+Shipping - PSA ID 72747973. If you look up this card, you get to
this page which basically verifies...yep, it got a PSA10. To my naked eye, it looks a tiny bit OC but I can't really tell from the photo if that's just my eyes being funky. But that's a 2.5-3x price on a PSA9 (where the grader absolutely lost money on this). But that's what you get -the PSA 10 generally runs $25-$35.
There is a TAG10 on eBay that sold for $37 CAD - so similar price. TAG ID Y5992808 - will get you to this
DIG Report which gives you the full grade (950/1000, TAG10), and then details on the front and back rating, centering, corner, surface, and edge /1000 scores, dimensions, locations of surface damage. You know where it ranks in TAG's database as well so you can differentiate between cards of similar grades.
There is no universe where as a buyer, you're going to have more confidence buying that PSA10 than the TAG10 grade wise - it's not to say it's a worse card or in worse condition, but the TAG info gives you a thorough review of what is or is not wrong with your card and PSA is...a number. Yet, a
PSA9 Ohtani RC From the complete set sold for $70 and a
TAG9 of that same rookie sold for...$17.50+Shipping. I am sure some of the issue is that you couldn't look up the TAG Cert Number (blurry photo) but that's the risk - you either settle for a non-transparent grade or you accept that if you do want to sell a card, you will not be maximizing your income off of the card.
My primary sports card breaker does SGC submissions and as much as I'd love to submit a bunch of things with them as I like their slabs and the reputation is good, SGC often just doesn't pull what PSA does outside of vintage. I might still submit some pure PC stuff to TAG because the clear slabs are sleek and I really do think they give a LOT more in terms of understanding your cards overall condition than PSA, but KFP is right in terms of market - if you're grading to potentially sell it's really difficult to justify anything but PSA and
maybe SGC or CGC dependent on card age, type, market (like CGC for Pokemon is way different than CGC for like...Basketball, SGC for 2020s TCG is way different than 1960s MLB)
(The funny thing is TAG got a lot of posts on the baseballcards subreddit to the point where they got called out for people trying to covertly promote it, which I still think was veiled promotion, but it kind of hurt their reputation there despite being pretty legit)