As I understand it, btrfs is considered OK for file systems running on
systems that don't suffer from power failure, so for writing an image
and testing it this should be fine.
So, what do people think about switching?
I too would be considered about filesystem integrity given the number of times I'm forced to yank the power cord on my board.
What speed class card are you using though? I tried a low-end one at first and quickly decided the extra US$5 for a class 6 card (San Disk Extreme) paid back the next time I used l-m-c.