He does have a point, there is quite a lot that 'doesn't' work out of the box, DVD playback anyone? Yes you can 'get' it to work, but its not 'out of the box' like quite a lot of things that are 'standard' in other OS's.
The overall GUI is very clunky, still 80's looking, quite Win 3.1 in window design, this doesn't seem to have moved on in years, whereas Win7 and Mac OS are light years ahead. Yes again you can jazz it up by adding stuff and tweaking with the settings, if you have the time, but again not out of the box.
After a hard day at the office, not many of us have time to sit down for hours and hours, fiddling with the computer to get it to do what we want, some of us have a 'Life'!
I do use Ubuntu, its my main OS, I like it, (I know that doesn't come across), but its never going to convince the M$ or Mac crowd over, due to its severe lack of functionality, dated user interface and poor user experience, there is a Lot of work still to do.