Unity = for mom and pop with its “software store” — HEAVILY commercialized crap.
Gnome 2 = usable. Good.
LXDE = kinda bare threads. Ugly font. The font in the default terminal (lxterminal) is one ugly face! Probably due to bad anti-aliasing. LXDE's look'n'feel is kinda like Windows 95.
I think Gnome 2 or Xfce would be my choice forward.
in summary, when it comes to UI, am highly efficiency and pure functionality oriented, but everything i judge by more scientific grounds as much as possible, not by Geeking HABIT or Culture.
o btw, so, it's been like 10 years since i tried Linux. Of all these wm i've tried, when compared to Windows today (Window 7), am sorry to say, the Linuxes are all clunky, error prone, less features, by FAR. (i was thinking and wishing it to be otherwise, but am sorry to say this is simply unbiased fact) And, OS X's UI, on prettiness, functionality, ease of use, robustness, is another level up than Windows.
humm… so, it looks like, after 10 years, things haven't changed much, really.