I always thought Unity was all right in general, Compiz in particular has a wealth of functionality that just doesn't exist yet in Gnome3. The Unity dock is very good, particularly the way it deals with multiple application windows (broadly: first click: bring LRU to front, second click: expose all application windows).
But I still think the "Lenses" thing is just awful. It's fine for starting a specific application by typing in the name (the most basic "Quicksilver" functionality). It used to be really slow, but I think that's better now. It still sucks for application discovery, which the old hierarchical menu excels at. And the other lenses are mostly just silly: you've got this simplistic interface, and people are trying to shoehorn all kinds of use cases into it. Look at [0] and [1]. Some of those would be much more useful if they weren't limited by the restrictions of the Lens framework (others are just hopeless).
I'm giving Unity another shot these days and it's still frustrating me. I still find it significantly less convenient than the old Gnome 2 was, and that's after tweaking some of the more annoying offenders (simple Alt press bringing up a huge window).
For example, the "expose" feature shows a bunch of windows and lets you browse between them with the arrows. However, the lowered the contrast between them so much that I really have no idea which window I'm currently selecting.
Similarly, multiple windows barely show which is in focus due to this weird fetish for near 0 contrast.
Also, I'm still missing my task list, wanting to know what I've been using to remind me where I stand in each desktop. The little arrows are much less helpful.
When pressing winkey, it waits something like a whole second before it shows me the unity-bar's numbering, and without those, the keyboard is useless. I use the keyboard to work faster, not slower, but Unity is slowing me down here as well.
These are just the criticisms off the top of my head, but overall it's been a pretty annoying week or so with Unity.
But I still think the "Lenses" thing is just awful. It's fine for starting a specific application by typing in the name (the most basic "Quicksilver" functionality). It used to be really slow, but I think that's better now. It still sucks for application discovery, which the old hierarchical menu excels at. And the other lenses are mostly just silly: you've got this simplistic interface, and people are trying to shoehorn all kinds of use cases into it. Look at [0] and [1]. Some of those would be much more useful if they weren't limited by the restrictions of the Lens framework (others are just hopeless).
Fortunately the lenses are easy enough to ignore.
[0] http://www.omgubuntu.co.uk/2012/01/10-unity-lenses-scopes [1] http://askubuntu.com/questions/38772/what-lenses-for-unity-a...