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I’ve used the Airline as my main tonearm since around 2007 or so. It replaced a Triplanar which was mounted on a Kuzma Reference turntable. The Airline has been used with the much heavier Kuzma XL.
The arm itself is extremely well fabricated and I have had no issues with it whatsoever. Set up is pretty easy too, once you become familiar with its behavior. I’d say the biggest drawback is the need to use a fairly substantial air compressor. The one supplied with the arm- a Sil-Aire made in Italy-- is a quality compressor, quiet as far as those things go, but you don’t want it near the listening room. I’ve experimented with several different compressors, not because of sonics but simply because I wanted to minimize the amount of time I had to spend dealing with it. The larger compressor tank will hold more air (at one point I was running one with a 13 gallon tank), but requires more time to fill when the motor kicks on.
Sil-Aire has a facility here in the States and they’ve been great to deal with over the years- they know these things inside out, though they are not audiophiles and use on a tonearm is one of many different applications for these things. Right now, I’m using an oil-less medical grade unit which has a tiny tank made of stainless and is 10db louder than the oil-based compressors. I had built a silencer box for a larger compressor, and this fits into it. I’m running a good distance of air hose through the walls to get to the point of use where I have a set of filters for particulates and oil that the compressed air (@ 65psi) must pass through before reaching the arm.
In terms of maintenance, I clean the shaft along which the air bearing runs with lab grade alcohol wipes to make sure there is no lint or room debris on the shaft. I’m told this is not necessary, but it makes me feel more confident that the path the bearing is running on is clean. If you go to this link, and scroll through it, you will see the arm and the compressor with silencer box. [url]https://thevinylpress.com/system-notes-austin-2017/[/url]
Kuzma support in the States is extremely good if you are located here, due to Scot Markwell, a well regarded person in the industry. If you have reason to call the factory in Slovenia, you can also speak to Franc, who is courteous and unfailingly helpful.
The only cautionary note I would make is that in your effort to eliminate some perceived compromise in a conventional arm, you are taking on a whole other set of operating parameters. Though I’ve had zero issues with the arm, I had never planned to be a compressor mechanic. I’m getting pretty good at it. :)

I have not made direct long term comparisons between the Airline and a conventional arm on my set-up due to the inability to get the Minus K to balance correctly with the additional weight (30 lbs) of a second arm pod and the requirement of a single center of mass to get the Minus K to "float" as it should. My judgment of sonics attributable to the linear arm (which I did not comment on above) may also be influenced by the fact that I went from a very good self-isolating table (the Kuzma Reference) to a very high mass table with no suspension (the XL). That said, what I hear is rock solid images in a very spacious presentation with no noise (unless there is some flaw in the particular pressing). I can best describe it by saying that you notice no "halo" around the sound coming from the turntable-- something that is most noticeable when it is absent.  Whether that is solely attributable to the arm, or the combination of the arm with the very high mass table is not clear.
The Airline (and this may hold true for the ET2 as well) also seems to like a lower compliance cartridge. After years of running the usual high-end Lyra and Airtight cartridges, the synergy with the Koetsu stone bodies has given me the best sound I've ever had from this system. That cartridge change has also rectified one of my chief complaints about the sound of my system- the lack of convincing, deep bass, which is often a complaint about these arms. On double bass, or the lowest registers of a concert grand,  I now get a fully fleshed out image that not only has real gravitas, but also the sort of dimensionality in the bass for which the Koetsu is best known in the midrange. These qualities keep me soldiering on despite the complications of running this high mass rig in an old house with springy floors and air hoses and compressor. Perhaps when our current health crisis subsides, you can make some meaningful comparisons and judge this for yourself.