The short answer is No. The existence of environments such as Xfce and LXDE is not by accident. They appeared out of needs - main of them being less resource usage i.e. better performance at less resources available.
Issue No. 2 - inherent Unity flaw:
It uses long animations - Unity at its best will feel 'smooth' but never 'super fast'
Unlike many people say animations for main Unity elements like Dash cannot be disabled: How to disable all Unity animations?
Issue No. 3 - bugs in Unity:
I can't judge whether it has more bugs than other environments or shells but there are some issues in Unity that degrade overall experience e.g. Dash maximized opens up twice as long as Dash at standard size, see http://askubuntu.com/a/169634/29347 Since Unity relays on Compiz as another layer, I'd say it's even more prone to bugs.
My personal recommendation for those with modest rigs or even those with modern hardware but not wanting to 'wait for animations to finish': Lubuntu (with LXDE)
On a side note:
Unity as well as GNOME cause gaming performance degradation. These two I know of. Try digging on phoronix.com a little.