Experience With Linear Tracking Turntables

Walker Proscenium, Rockport Sirius, Kuzma Airline, Forsell Air Reference, Air Tangent all represent top tier linear tracking tonearms. I know there are very good pivot arms too, but a good air bearing type linear arm is great. I happen to own the Maplenoll Apollo and Ariadne which are air bearing arms. I would not trade my turntable for any other table. 

I only recently came to appreciate the B&O MI cartridge, MMC1.  It weighs only a few grams, and tracks at 1.0g with very high compliance. On my Dynavector DV505 tonearm with a very light headshell on my Lenco, it sounded divine driving my Beveridge system.  Now on my Triplanar tonearm into my Sound Lab ESL system, it also sounds fantastic.  I purchased the MMC1 NOS several years ago, but it sat in its container for quite a few years before I decided to listen to it, rather than to sell it without having heard it.  Now I rank it among the top 3 or so that I have ever heard in either of my two systems.  So this makes me wonder how this cartridge might sound in one of the original B&O SL tonearms on a B&O turntable.  B&O made quality components but with a nod to interior design of that era, which probably is why they were largely ignored by true audiophile cognoscenti.  Too chic.
Also, I am now very favorably disposed to SoundSmith MI type cartridges, since Ledermann is a big fan of the B&O cartridges and started his business as a repairer of them.

If I recall, the B&O LT turntables moved the arm mechanically by detecting slight changes to the geometry of the arm.  In other words, they used tracking error measurements to correct the position of the arm.  

I remember hearing them back in the day.  I wasn't terribly impressed.  Especially with slightly off center records.

The Mitsubishi LT-20 (or LT-22) linear trackers are excellent. They allow VTA adjustment, and they accept a standard SME headshell. This table with a moving coil micro linear stylus will absolutely wipe the floor with 99.9% of the turntables on the used and new market. 

I owned a couple of the B&O tables with linear tracking arms in the past (3300 and 8002) as well as the Technics SL-10. While I was very happy with all 3 tables, I kept going back to my direct drive tables with pivot tonearms, but like @lewm I came to really appreciate the B&O cartridges of which I have the MMC1 and 2, as well as a Soundsmith Carmen II. Now I use a PTP Audio table with two pivot tonearms mounted on it, and while I am still intrigued with linear tracking options, I don't see the need to revisit them.