Drew- I just bought an HGA (Hybrid Grade Approach) graded 1977 Topps
Paul Molitor rookie at a show last week. A dealer there other than the one
I bought the Molitor from, had for sale approximately 30 HGA graded cards
as well. I like the Molitor and think they got it exactly right at 7.5. This
company may be the droid you are seeking
I have also owned a couple CSG graded cards and transacted them with
other collectors, and I agreed with the grades on those cards. Speaking
exclusively about grading accuracy, the sample size I've seen is no worse
than PSA's accuracy, and is likely better (although that's not a high bar
to climb).
These are the only 2 I've experimented with in the past year. They clearly
lack the popularity of the Big 3 up to this point; however, I think the same
logic with their cards applies to that of dealing with the Big 3- buy the card,
not the holder.
Trent King