The IQ issue is a tricky one, because I'm quite happy with the IQ I get from m4/3 - but so long as it doesn't get worse in the corners then I'm happy. Likewise for CA, I'm content with the performance of the 20 & 45 Lumixes, but wouldn't want anything more abberant.
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Really it's the manual lens/rangefinder, and seeing outside the frame that holds my interest. I'm almost sure I wouldn't miss AF at all (especially this fly-by-wire sort) and I definately miss DoF scales and a hard infinity stop. I've tried manual lenses on m4/3 but it's just not right. The M8.2 seems like it ticks all the boxes.
Just my thoughts (I have the E-PL1, G1, M8, M9):
* There is nothing like shooting with a Leica.. true. On the other hand, its not for everyone. I always recommend trying to figure a way to rent or borrow one for a while. If not, a film rangefinder of some sort for a taste. The whole experience shooting with a rangefinder is different... the whole experience of shooting with a Leica more so.
* If m43 provides you with 90% of what you enjoy and it keeps you happy, I'm more inclined to believe you have already found the perfect system for you.
* m43 with an brightline viewfinder of approximate equivalent focal length should provide you framing and still see outside the frame. That's how I shoot with the LX3.
* As you have already well know, Leica anything (even vintage) is expensive. V/C is going to be more affordable but still relatively pricey. Older lenses from the 50s often need a CLA. The service can be difficult to find locally and pricey as well. If the M8 stretches your budget, the lenses will sure throw you over it .
* M8 and M8.2 differences were subtle. M8 upgrades were done in whatever combinations of options the customer requested... so there are variations in the used market. IMO, I prefer the M8 for its 1/8000 speed and cheaper prices.
My favorite focal lengths on the M8 is by far the 35mm and 75mm (Summarits). I did find the 1.3x crop a bit unusual/odd. For example, the Noctilux 50mm f/1 seemed to lost some of its character and because a mild telephoto FOV feels off.. too tight. It gains the 24mm framelines but looses the 90mm.
My favorite focal lengths on the M9 is the 24mm (Elmarit), 50mm (Summilux asph), and 90mm (Summarit). I use the Panny LX3 viewfinder with the 24mm. I can use it just like I did with film. Its expensive and I would agree overpriced but I still absolutely love it. It doesn't work well with my 12mm heliar although I've read people have a work around.
The M9 IMO was suppose to be the first Digital rangefinder from Leica. The M8 is still really good but in some ways still a compromise to rush to market after Epson embarrassed them with the R-D1 release. The M8 is so good that I "failed" to sell it (as promised to my wife . lol) when I purchased the M9. Sometimes I still head out the door with just the M8 and its two Summarits.