without knowing the bitrate implementation on the oly and panasonic, it's very hard to compare MJPEG from one and AVCHD from the other. If you're not sensitive to minor quality differences, the two will probably be the same for you.
That being said, the one thing that can be said is MJPEG is easier to edit than AVCHD. Depending on the hardware/software you use, you might find it much more difficult to edit AVCHD files than MJPEG files.
That being said, the one thing that can be said is MJPEG is easier to edit than AVCHD. Depending on the hardware/software you use, you might find it much more difficult to edit AVCHD files than MJPEG files.