Here are some screenshot comparisons between v1.0 and v2.0 AVCHDs, showing the difference in the over-all picture quality:
http://screenshotcomparison.com/comparison/87208/picture:0
http://screenshotcomparison.com/comparison/87208/picture:1
http://screenshotcomparison.com/comparison/87208/picture:2
http://screenshotcomparison.com/comparison/87208/picture:3
Since you can only compare two sources this way, I decided for the AVCHD, as it is a more fair comparison. Though the difference between the v2.0 AVCHD and MKV is actually super tiny - not that it's not there but you can only really see it in full-screen on a larger TV or monitor.