Simple looking, and uncluttered, these posters send exactly the right kind of message. Great imagery with the lock.
The XP screen is the best one, since it appropriately associates the feeling of restriction to the operating system itself.
The blank screen is interesting too, since Ubuntu can bring new life to older computers, but the lock imagery doesn't fit that.
I don't like the blue screen of death. It brings up the issue of stability, which is an advantage that Ubuntu has, but I'm not sure its a big enough problem for most users, and again does not fit with the great lock imagery.
In my opinion, the blank and BSoD screen posters should be reworded with the lock removed, then submitted separately. The BSoD text could be changed to "Fed up with Windows? Discover reliability with..." and the blank one could be changed to "Want more from your computer? Expand your capabilities with..."
Another pointer would be to bold the words free. Potentially the "fast" "reliable" and "powerful" words too.
More information about formatting options
___ ____ _ / _ \ |___ \ | |__ __ __ ___ _ _ | | | | __) | | '_ \ \ \/ / / _ \ | | | | | |_| | / __/ | | | | > < | __/ | |_| | \__\_\ |_____| |_| |_| /_/\_\ \___| \__, | |___/