I find the Ace turn better than Indy. (Sharper and deeper) but also feel more comfortable and predictable on center than Indy.
Classics turn slightly better than Af1s. If there was an 8.75" Ace in a Classic, I'd probably stick to that.
Stage 4 Indy turn even better than Ace classics but have some instability on center like Stage 11s. ts just not as smooth or as predictable turn as an Ace. This might be height related.
I also prefer the pop feel on Ace. It suits my sluggishness. (If I were a young sprightly man on my game, I think the Thunder pop would be better.)
I think my brain and body are just used to Ace now, so I'm, certainly biased. However, its really not that hard to adapt between Ace and Indy and I don't think it is worth switching unless you really need new trucks.