I understood Picoarmor were just US agents for 3mm Oddzial Osmy stuff, rather than making their own 3mm figures. Am I mistaken?
Picoarmor has consistently not made a feature of the Oddzial Osmy name on its site to the extent that it is quite common to see the range mentioned only as Picoarmor in the US.
Fighting 15s also stocks Oddzial Osmy in the UK, and has been doing so since 2005. Magister Militum is a relative newcomer. Richard at MM, however, has also moved into making his own 3mm figures for periods not covered by Oddzial Osmy, whereas I have simply produced a few Middle Eastern buildings to test the water.
It is literally a small market, and in my experience the internet talks it up substantially. Stockists come and go: the UK has lost KR Games/1to600miniatures, and various European sites have stocked and then dropped the range (for example, Adelbertus). I keep the faith with the range because I can support it through sales of AB and Eureka Miniatures, and have had the fortune to build up stocks gradually since the range’s inception rather than making one massive investment.