Basik LV-X (much different and better arm)
Basik Plus (similar but better due to fixed headshell)
Akito 1 (better musically but subject to bearing problems over time)
Akito 2 (much better, built in Scotland)
Akito 3 (much better yet with machined from solid bearing yoke parts, improved, near Ekos level, bearings)
Ittok LVII (I would say that it and the Akito 3 are in about the same league, both are quite good)
Ittok LVIII (improvements to attachment of headshell to arm tube and tube to bearing assembly, other improvements)
Ittok LVIII mk2 (Improvements to bearings and new cueing/arm rest/anti-skating platform. Very nice arm often referred to as the baby Ekos)
Ekos 1 (Some have had problems with the tracking force dial grease solidifying and making it difficult or impossible to to turn. A few units have had bearing problems.)
Ekos 2 (Improved bearings and attachment of the parts to each other. A very good arm. Only units with a serial number of 9000 and higher are still repairable by Linn.)
Ekos SE (Complete redesign of Ekos 2 with the cueing device and cartridge wires being the only shared parts. Much improved horizontal bearing system, improved vertical bearings, improved materials: machined from aluminum billet headshell, titanium arm tube, stainless steel bearing structure. Excellent arm.)
Ekos SE/1 (Updated SE with longer and strengthened headshell to accommodate larger cartridges and shorter arm tube to compensate. Stated to not be a musical improvement but many, myself included, have found the musical improvement significant and worthwhile. The best arm I have heard.)
Not being able to compare the new Arko to the older arms above I'm not sure exactly where it slots in. I would expect it is likely better than any Ittok but would personally be surprised if it could outperform an Ekos 2 musically. But I could be wrong.
Note that arms before the Ekos 2 #9000 and the Akito before serial number 103413 will not be serviced by Linn. That includes all the Ittoks but in my experience they fail less than any of the other arms besides Ekos 2 and SEs. Black Ittoks were just a finish variation but of the few Ittoks I have seen that were bad Black ones have been prevalent - but it is still a tiny amount. I also find the Akito arm cable (which was the original T.Kable) to be the most musical arm cable.