Hi there,
The memory card issue was experienced by many of the early batches of M9s. My M9 died 3days after I got it from the AD, and I got them to replace it with another within a week. But I think that issue should be largely resolved by now. My "replacement" M9 has been ok for the last 11 months. I have not experienced the issue (touch wood) you mentioned on your 2nd camera.
I also have an MP which has worked very well since I bought it slightly more than a year ago.
I am assuming your M9s have both been fixed since?
My M9 got one of the latest serial no, so I think selectively this is still an issue for some bodies. Bought mine directly from Germany. Mine should be coming back soon so keeping my fingers crossed.
Without sounding like a rant, the customer service in solms is also lacking which adds to the unhappiness.