I fitted one to my most recent build a few months ago.
I was very sceptical due to their past reputation, but it was reported to have been deliberately over-engineered and came with a long warranty. And feedback from owners was good.
It has a very high-quality feel, better finish than OneUp and other mid-range droppers – closer to BikeYoke but with a caveat or two.
Done 600km on it already, still early days but a reasonable amount of use, and it feels barely broken in.
To those caveats I mentioned – it’s slow to return and the speed is non-adjustable. You can ride around this but it takes a bit of getting used to.
Also the lever, while nice, is quite stiff to push on my set-up, another thing you have to get used to.
I wasn’t thinking about these things until I jumped back on my big bike with an SDG Tellis post, which is super-smooth, fast and has a particularly light actuation.
Anyway, I’ve ordered another Highline, might as well at that price since I Have two 30.9 bikes.