My post is directed only to the M-2 device as I don’t have any experience with other 35mm lens adapters. There is something about the Sony/Fujinon lens as it has trouble focusing in macro on such a small plain. As you said the Letus may be a better choice, but I have the EX3 and the Fujinon 2/3 lens adapter together with the Fujinon XA17x7.6BERM 17x 2/3″ and it is really nice. What kills me is that Red Rock Micro rep at NAB knew about the issues with the EX series and sold it to me anyway, then he became way to busy when I needed his help. The latch from the M-2 case broke while I opened it for the first time and not one customer rep even offered to replace it.
Good Luck
Michael Palmer