« on: May 24, 2012, 05:21:51 PM »
As others have mentioned, the backlight issue only happens in very rare cases - I have an early serial # body as well and I'm not worried about it at all, if I do ever find my self outside of a dark cave, I'll just hit the exposure comp button after reviewing the result - pretty the same as you would do with every other shot with tricky light conditions.
I've personally never used the JPG mode on the camera, I don't trust build in jpg processing and I know it'll never tell the story I want to tell so even in time constrained situations I'll do quick 10 second processing step in lightroom, so I don't have any personal experience with how I like or dislike the jpg processing - as suggested you can tweak a lot of the build in jpg processing in the image style menu though so chances are perhaps that will improve the outcome for you? (ie in your case you might want to boost the sharpness a fair bit?)
For the 24-105 kit lens, it's a known trade off - it's a very light lens with a very usable range and pretty decent image stabilization, however what you gain in that versatility, affordability and portability you do pay for in absolute sharpness, contrast, saturation and some distortion. The distortion you can easily fix in Lightroom (or camera raw, etc) with the build in tools, for the rest - if you want the sharpest photo possible the (heavier and more expensive) 24-70 or primes will give a better result, it's all about the trade offs and what you want to use it for.
I personally see no need to return my body at all - the raws are spectacular, the light leak issue is barely an issue at all and easy to work around in the remote case where it does show up, and while I do have the 24-105 lens as well I know what situation it's good for (light walk around lens for casual shots) and what situations it isn't enough (shots I would consider publishing).