Got to agree, it's the best Linux desktop distro ever and has some great solutions to your regular pesky Linux issues Nevertheless, it is not perfect and here are some of my pet peeves which stop me from giving Ubuntu a 10/10 rating.
Read it in this blog
Does not recognize wide-screen monitors
My brand new 19″ widescreen Acer just doesn't get recognized properly, in particular it's 1440×900 resolution. I had to manually edit /etc/X11/xorg.conf to give me that option, but I still have not been able to force it to use 75Hz refresh rate, Ubuntu shows me only 50Hz, 60Hz and 61Hz in my options.
Responsibility: Ubuntu. Needs to improve hardware detection