Thanks Matt, but having never owned or used any Leica at all, I was really after details of the M10 VF such as eyepoint and can you see all of the VF view and the lens frames?
Sorry, Mike, should have been more explicit. I can see the 35mm frame lines okay, but can't see all the 28mm framelines without squinting; but I had word from someone with loads of experience that the latter is true for most people. The VF is fantastically big and bright though - the best optical view there is in my experience, and you can indeed always see what's going on outside of the frame. That's even true if you have troubles spotting all the framelines at once.
However, framing is - by nature - less than perfect unless you use LiveView, but that's counter-intuitive in many situations if you don't have the EVF on the camera or the camera on a tripod - holding the camera so that you can see the screen and focus at the same time isn't comfortable at all. I got used to working with the viewfinder extremely quickly - because the immediacy is just unsurpassable, and using the rangefinder is so nice and precise. Even so, it certainly isn't the most accurate way of framing. But since this is true for all RF cameras anyway, I don't mind (much) - though actually, Leica's frame lines are quite impressively reliable and I get the image I want most of the time. If in doubt, frame (slightly) loosely.
As for finder blockage, some lenses will do that. My Summicron and my Zeiss Biogon C don't even come close to obscuring part of the frame, and neither does the Elmarit-M 90mm (which is surprising because it's not a small lens). But with the Elmarit-M 28mm f/2.8 (that's not the latest lens but its predecessor - without ASPH designation), the lens is always filling the lower right corner - and if I use the hood (which I usually don't - but it's not necessary anyway), it becomes obstrusive. It takes some getting used to, but in practise has never prevented me from taking the shot I wanted. Another lens that blocks the lower right corner is the Voigtländer Ultron 35mm f/1.7 (a great lens for its price!), but again, in use, I hardly notice it.
All in all, yes, it's a bit archaic at first and takes some getting used to, but once you are, it's a wonderful way of framing and shooting; in fact, in some cases, I found it painful to have to go back: I shot a bit of documentary with the D5500 (which is a camera very well suited for such a task, it's small, fast and has great lenses available - like the Sigma 18-35mm f/1.8 Art ...) shortly after coming back from shooting the M10 in Scotland and found the D5500's pentamirror finder downright claustrophobic - I knew that the viewfinder was rather small and somewhat dark, but I hadn't noticed how bad it really was before. The D750's big, bright pentaprism is almost as nice as the M10 - but that camera is a lot bulkier. The Sony A7 II's EVF doesn't really compare - though it is nice and big as well, but it lacks the clarity and smoothness of optical finders. I must say that I think the Z7's finder came close enough, though - quite a feat ...
M.