Compared to many other keyboards I've used, Niz Plum has been better for sure, but compared to my Realforce and HHKB boards, I think the build quality could use a bit of work. On the first Plum board I had, the spacebar broke, so I had to return it to Amazon in exchange for another one. The feel on the second one felt really scratchy, so I had to go ahead and lube it, and that helped. It also came with these annoying costar stabilizers on some of the keys where as I don't have to worry about any of that so much with the other electrocapacitive boards I use already all the time.
Also, Plum doesn't have those special angled keycaps that Topre has, but other than that, they are enjoyable to use in their own right, but I much prefer the quality and experience of typing on a Realforce for sure on both variable weight and 55g domes depending on what I feel like typing on for that day.
I tried modding my Niz Plum with BKE Redux Ultra Light domes, but that didn't work out for me, and there were whole areas that would not register a keystroke, so I had to reinstall the old stock dome sheet it had. I would definitely give selling it another go if I could so I can save up for a Leopold with numpad to try out next. I keep hearing those have some of the best stock Topre typing experience you can find out there.