Yeah, H8-80 is totally a natural switch from D09c on FH. Bit slower, not as stretchy as D09c, not nearly as bouncy. The 38 deg black sheet kinda feels like a new D09c regarding hardness. D09c did soften up a bit over time, I guess H8-80 will also do something similar as Chinese rubbers tend to have a break in period.
Interestingly on just flat hits H8-80 is better than D09c. More stable, hits down on the blade easier and more consistently. Usually Chinese rubbers are not particularly good on flat hits. This one is fine.
I'm not sure about the spin tho, it seems super spinny. It can make a similar arch as D09c, but doesn't have that speed so I guess it's not as spinny. But it's not lacking.
For incoming spin it's more sensitive, it blocks topspins back at a higher angle than D09c, not as forgiving on racket angle as D09c, but after some adjustment it was fine. I didn't struggle with it at all.
Opening loops were a bit of a hard one. Using the D09c movement it was usable, but not so dangerous, which is why I'm a bit torn on the spin. The sponge doesn't have the bounce by itself so if you just use the sponge and rubber it's kinda lackluster. I found on opening loops it's better to just open the racket angle even more than with D09c and try to hit down on the blade as well. That way it was much better. It makes a high arch so it works out magically. D09c is also usable this way so it wasn't a foreign technique. Playing directly and forward is rewarded with both rubbers.
I do have a gripe with D09c on opening loops. It can hold the ball a bit too long and sometimes that "floats" the ball long for me. H8-80 didn't do that so far.
Over the table play is vastly superior with H8-80. Ball can be kept closer to the net, service receive is more stable, flicks are much better. I really love Chinese rubbers for flicks, they are just so direct and reliable, while Euro-Jap rubbers tend to have a mind of their own sometimes.
On BH it was a bigger change. Compared to D64 it's slower without a question. But not slow compared to a "normal" rubber. The 37deg is a bit bouncier, easier to use on BH. D64 totally has a mind of it's own sometimes. The topsheet and the sponge are not very in sync on weak shots and sometimes it shoots the ball long, sometimes it feels just right. If you hit hard it doesn't do this but weak hits it's a crapshoot. H8-80 doesn't do this, on a VIS speed blade it is fast enough to put enough pressure on the opponent even from a relatively weak hit. I guess everything applies to it which I mentioned for forehand. It has more spin than D64 for sure, but also needs to be hit down on the blade. Open racket angle was surprisingly rewarding, heavily cut balls could be pulled up very well. Open angle and hit down on the blade, this is totally the most important thing about it. If you have this everything can be pulled up.
The sponge is dull enough to soak up some heavy topspins and even flat hits. I'm a lefty so I get a lot on my BH.
Does Dignics with double the cost? Kinda... but depends. Dignics is lighter. 09c is like 10% lighter, that is significant. D64 is like 10% lighter than D09c. So if you want a light setup unfortunately Butterfly is still far the best. Possibly D09c has more spin, definitely more bounce, more speed from back court.
On the other hand H8-80 is better over the table and is not too shabby from back either. It seems more dependable too, it won't overwrite your shot with some weird catapult effect.
I used my Nexy Eucrasia to test H8-80, gonna leave them on, it's a good combo. A Viscaria would be a good option too. I wouldn't use anything much slower opr flexier tho. Something faster might be a good idea. Since D09c and H8-80 make a tall arch and they are both good when they hit down on the blade I would use a stiffer blade. Just like the Eucrasia is stiffer than a VIS, or maybe the Tibhar Drinkhall powerspin carbon, Ovtcharov ALC, Carbonado 245/290, I wouldn't rule out the Garaydia or Primorac carbon as a good combo. Hinoki has a good grip, I think it could work exceptionally well.