I'm more or less a newbie, and I can say that mint has proven nearly flawless for me. I've played with linux, off and on, going back to before Red Hat, but it there was always something that prevented me from really learning it. Hardware issues, not knowing what software to get and where to get it ect. I've watched it evolve and in the last few years I'm amazed at how far it has come in general. Just to give you an idea, I have and HTPC/home server and a desktop that are mostly used by the wife and kids which are both running windows 8. My laptop is my main machine which is running windows 7/mint 14 cinammon/ubuntu 12.10 atm.
There are certain basic things I look for in an operating system. First and foremost is installing it and knowing the hardware is going to work. The best OS in the world is useless if you can't use the hardware you have. Especially when searching for the issue typically leads you to advice that may or may not be relevent because it refers to different versions and/or distributions. I don't mind tweaking a little(hell I have a whole list I have to go through to make windows usable everytime I install it!) but I really don't want to read for a week and experiment to try and get a wireless driver to work! At that point it becomes a labor of love and I don't love any OS that much!
Score: mint 1 Ubuntu 0
Ubuntu had problems initially recognizing my wireless. It corrected itself somehow, but now connecting to my vpn is having problems. Mint: flawless
The Next consideration is navigating the interface. Going from windows to mint, if you even just have a vague knowledge of linux, is almost seamless. Ubuntu is pretty but not yet polished enough or customizable enough IMO. It's a work in progress. I can see where they are going but it's not there yet.
mint 2 Ubuntu .5
Finally, software. Both repositories look well stocked, so I will confine myself to preinstalled programs. The best thing linux has going for it is the ability to include an enormous amount of software preinstalled. Most distributions don't seem to use it as well as they could for one reason or another. Mint has more than any windows installation ever dreamed of, but it's not bloated. Firefox, Thunderbird, open office/libre office, VLC, Gimp, RDP client, check. Throw in XBMC for a little entertainment and it's a nice package. Other than replacing the RDP client that was very buggy for me, I haven't had to touch anything for basic usage. Ubuntu... well I must say it was very strange scrolling through the repository and seeing price tags on linux programs! Ideology aside, if you're going to do that at least include VLC or some sort of DVD playback! I'll give mint the edge.
Final Score mint 3 Ubuntu 1
I realise not everyone thinks like me, but they should!