Uh Oh! I see bash Linux time again, specifically Ubuntu. Strange, I have so far installed it in around thirty odd PCs of various vintage at my institute, my own personal PCs have dual quad core and phenom, also a old VAIO laptop and a ASUS EEEPc. So far none have given me any issues whatsoever. Everything works and works well. As for free versus paid, lets see, I am like others an ex Windows users and till date I have tried out their latest and greatest, I won't use it even if were to be free. Few of my friends have gone through hell trying to upgrade from XP, BSODs are back with fervor again and not since ME it has been that bad. Btw, it has now progressed to Black SOD from blue, now thats innovation for sure. http://news.cnet.com/8301-13860_3-10406369-56.html
The best MS OS to come out was their unheralded WinXP64, had best of both worlds, XP's GUI with rock stable 2003 server core, match made in heaven. I had that as a free upgrade and with SP2, it was the best ever Windows to run on my PC till I went all Linux.
The original OP wanted to know if we like Ubuntu among other Linux distros, lets keep it that way and not make it the typical Win versus Lin mudfest.