I have the flux, and it’s pretty good! The trainer response to terrain is quick enough (maybe 2-3seconds), and erg mode works well. The things I like less about it are:
It’s very quiet when it provides most of the resistance (generally most of the time in erg mode). However, when you do intervals or when you’re in sim mode going down hill, so you’re in high gear, it can produce a fair amount of grindy noise. It’s not that loud, but it is noticeable.
Erg mode isn’t all that accurate (it jumps around quite a bit), and it makes short intervals difficult. I tend to compensate by dropping my cadence a bit (20s) just before an interval begins, so the resistance per revolution increases - this means that you can then jump to 110 rpm to get your power to the right level
The shim for 130mm hubs isn’t that well thought out - it’s a untextured washer which you clamp between your dropout and the unit, and essentially provides a slip point. I’ve not managed to shake my bike loose yet, but it does sometimes make a bit of a noise when I’m really shaking the bike.
It could be a little more stable, though it’s stable enough I guess.
I’m a little suspicious about the cadence sensor - I was riding today, and it was recording slightly iffy cadence - I was cooling down at ~70rpm, but it was still saying 85.
Basically, it’s pretty good - I’d give it a 8/10