The Leica S2 considering it's price has a bad reliability record.
I know 4 people that have these cameras and all 4 have had issues with it.
Nikon and Canon reliability in there pro models is stellar in comparison.
German engineering is way over rated.
My Mercedes is a piece of crap compared to my Honda minivan.
.... and my family is German ....
I'd be a bit careful of such pronouncements.
On the DWF website, where a bunch of early adopter pro wedding photographers have already pressed both the Nikon D800 and Canon 5D-III into service ... there are reports of issues with both cameras.
The D800 has a number of users reporting total lock-ups while shooting requiring a battery removal re-boot, and back-focusing issues when used in conjunction with SB-700 and 900 series focus assist speed-lights (but not with SB600 or 800s) ... this issue is also reported on DPReview.
Canon has suspended shipments of the 5D-III until the newly discovered light leak issue can be dealt with (hopefully with some firmware patch). Evidently the LCD light is affecting exposure metering in low light, and in bright sunlight, it also happens.
Anyone like me who went through the mirror box debacle with the pro body Canon 1DMK-II and Canon's initial denial, would beg to differ with your absolute pronouncement of superiority.
My trials and tribulations with Nikon Pro bodies and a reoccurring issue with their 24-70/2.8 (two copies broke in half because of a cheap pig-metal interior framework connection that was anything other than Nikon tough like some older Nikon lenses). A Nikon Pro body once lit up like a possessed Christmas tree and wiped all my images ... never figured that one out.
I DID have an issue with my S2 (which I reported in detail here on Get Dpi), received a loaner the next morning and my S2 picked up at the same time. Rather than a denial, I received an apology from Leica for the inconvenience. Since then, the S2 has performed flawlessly for me and has become my number one go-to camera.
The only cameras I've had zero issues with have been my two Sony A900s ... but I've had to send 2 lenses back to get better copies.
These are complex tools, any new camera design rushed to market for marketing reasons is ripe for issues.
-Marc