So I got myself 2 sheets of H8, both in 2.15mm, 37 and 40deg hardness. My biggest concern was their weight since many people reported they can go up to 53 and 55g cut to a 158x150mm blade. In fact this was the biggest reason I avoided the H8.
I do like the H8 topsheet a lot, be it on H8 or H8-80, it seems super consistent. Red, black, H8, H8-80 I got my red H8-80 when the H8-80 was released and then last year I bought a black one too and all the sheets were uniform and high quality.
I noticed that even in very humid conditions it does not have any issues. In high humidity or in cold many rubbers develop a waterfilm on them and that makes them a pain in the ass to use. Recently I had such an issue with a rubber while on my other side the H8-80 wasn't bothered by the humidity at all. Not sure if this is a design feature or not but it's welcome. I suppose in south China humidity is a big problem so maybe it was considered during development. Could be pure luck too tho, one never knows with China...
Back to H8 and its weight... it's really-really light. The 37deg cut is about ~44g, the 40deg is ~46g. With two sheets of H8-80 my racket was 188g assembled, from that the blade was 85-86g. Now I measured 179g assembled and I even left a bit of a rubber overhang.
I haven't tried them yet since I just assembled the racket but just from spin and bounce testing they feel more close to orange H3, definietely different to H8-80. I doubt they will be as bouncy as the H8-80, but they are not slow. They feel dead like a H3N, but if I put on a plastic foil they bounce really high.
If anything they remind me of Donic C2, but they're much lighter. I tried C2 on someone else's blade and I wasn't very impressed, it was an off- blade and I couldn't feel that particular blade under the C2 even if I smashed really hard. But C2 did make a lot of spin and it was very good at over the table counterspinning. But the C2's weight and the absolute lack of topsheet durability turned me away really quickly.