There's an interesting relationship between Leica, Sinar, and Panasonic for sure - Panasonic is seems to be behind the firmware in even the older Leica M series cameras, which are definitely made by Leica. The SL2 is essentially a Panasonic SR1 with a nicer body. The Leica S series medium format cameras use similiar looking firmware, and the the internals of the newest S3 power the Sinar S30|45 digital back. The Lux Cameras where just a different sticker though. The Q2, while also probably built by Panasonic, has no actual equal in terms of lenses. The lens they put on that body is stellar.

Having used an M camera briefly, they aren't worth the price new, but used they are really great values that are built like nothing else. When you tire of them, you can sell them back for what you paid, sometimes more!