Linux on the desktop has arrived, I thought. But I'll wait one more iteration before recommending it to my clients.
Dapper (2006) came and broke lots of things. Months later, all is well, mostly.
Once bitten, I didn't upgrade until Heron (2008) was released, and when I upgraded I did so one version behind, to Gutsy (2007); thinking that it should be stable.
Many things worked, but some, like video drivers and wireless networking, didn't. They'd been working fine since Badger.
By Jaunty (start 2009) everything was working. I still have this machine on Jaunty and no way am I upgrading it. It has some weird video behaviours, but Ubuntu has never bedded these down; it's always a bit of a lottery.
2010, I bought a new laptop (Sony Vaio). I loaded Lucid (2010 Long term support version) and I can't tell you issues it has. There is a dedicated group for resolving the issues. When I plug in the USB soundcard I use on the aforementioned machine -- it's playing now -- a card that has worked since Badger, the machine locks solid; it needs a power-down to restart it.
This is not an uncommmon story when dealing with Ubuntu. This and the vagaries of Shuttleworth. As he says, "This is not a democracy".
Ubuntu, like all things, is great when it works, but is constant shifting sand under your feet. And stability -- on the same machine, same OS -- is fundamental, imo. Ubuntu doesn't have this, and history has shown me that it is unlikely too. I've chosen to move away because of this.
Personally I've had less compatibility problems with Ubuntu than with Windows, but I don't expect everyone else to be the same.