There have been other conversations about this before, probably even a few more if you dig harder.
www.elitefourum.com/t/psa-10-unlimited-vs-psa-9-1st-edition-long-term/22088/1www.elitefourum.com/t/do-you-prefer-lower-graded-1st-editions-or-unlimited-psa-10/18408/1
There are multiple interpretations of the word “value”. The obvious one is financial value. If you want to compare prices between PSA 9 1st and unlimited 10, I’d recommend checking out www.pokemonprice.com/Sets If you’re asking about future value, any answer (including my past opinion in those threads) is just going to be totally speculative (i.e. mostly made up).
When it comes to collecting though, the important interpretation of “value” is what you, as a collector, value in your collection. For me, I collect a lot of PSA 9 1st ed wotc cards because I love the stamp and the money I put in (usually between $20 to $100 per card) vs what I get from it (a pack fresh card, already graded) is more value per dollar for me than paying multiple hundreds of dollars for a PSA 10 version which is just slightly better (usually). I don’t collect PSA 10 unlimited because I just don’t personally value unlimited cards at all.
So, you have to determine what you value more yourself. You have already said that you prefer a gem card over the significance of the 1st edition stamp so it sounds like you may already have your answer.
A few things to note, keep in mind my own collecting biases:
- PSA 9 1st edition is far more available than unlimited 10s and easier to find (important if you’re looking to build sets)- generally I see more interest in 1st ed 9 than PSA 10 unlimited (# of sales, people showing off their collection, etc)- a PSA 10 isn’t necessarily a flawless card, make sure you’re satisfied with what a 10 looks like before committing to that option