I’ve used desktop Linux for 15 years, and for all these years, it’s a continuous path of failures and sorry state.
Anyone still remembers KDE? KDE2 wasn’t so great, but KDE3 improved a lot and was really pleasant to use. Heck, no, the developers had to introduce the chaotic and unstable KDE4 – user base dramatically dropped and nobody has confidence in KDE anymore.
Gnome? Became even more popular after KDE4 was introduced. Unfortunately, Gnome developers, much as most Linux desktop developers, don’t learn on success of the others, rather, they repeat the errors of the others (KDE4). So Gnome 3 made it to the world, with users leaving and having same mixed feelings about it, just like they have with KDE4.
The new kid on the block, Unity, is as controversial and annoys a lot of its user with its inconsistency.
There are others, too, like MATE, Cinnamon, Xfce, but they suffer from even more immaturity than their bigger brothers.
What do we have so far on the Linux desktop? No organised engineering, no long term plans, no QA, releasing alpha versions as stable products, in short, just total revolutions every couple of years.