You have to follow the bug reports if you rely on stuff, e.g. this bug in 12.04 (which was not in 10.04) https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/669481 has no released fix two years later - if you need your servers to consistently reboot after a power down without human intervention, you need to apply the fix manually (just inserting a line in a config file, but still ...). I know it says "fix released" - but after having to drive to reboot servers, I can assure you that is not the case.

Personally, I'd wait at least 3 months, and follow bug reports before switching.