Update
Feel : is definitely better than 8PS. Seems normal like MXJJS/70. Maybe can benefit from stringing 1 lb higher than usual.
On Ch1k0's feel scale where 1 is ZSpeed, 2 is JS8PS and 5 is MX80, JS10 is a 3.5.
Can't wait to get some ZM62 Fire string on it asap when I can get my hands on some hopefully in the next 2 weeks.
Power : wow, just as ZSpeed is not a NS replacement, this is not a BS replacement. It's not balanced as per listed specs, but quite moderately head heavy. Much heavier swing wt than its dry specs would imply (81.8g, 36.1g, 297mm). I've never swung a 4U TK9000 or 8000, but this can't be too far off.
It's a whippy mini hammer, resulting in super effortless forehand and backhand clears... almost to the point where I thought I was playing with shuttles of the wrong speed.
Higher sweet spot : adjusting to it by holding higher up the handle. Very solid and crunchy strike.
Will add more when I think of more items.