Count me in as an affected user.
I have Medion Akoya E1210.
Upgraded from 10.4 to 10.10 and tried a lot to fix the problem.
When I boot with AC power connected, everything is fine (wifi) and resume also works.
When I boot on battery power, everything fine except after resume Wifi will not connect.
After a resume: when I remove the power cord, I first get a warning that the battery is extremely low (however it also indicates that it is 98% full). At that moment also wifi disconnects and goes on searching for a network forever. If I leave the cord unplugged the system crashes eventually. When I plug the power back in, wifi connects again.