First off, I think it's important to state that any mention of 'eastern' and 'western' cultures is purely in reference to traditional polarization and simply serves as a generalised convenience rather than a modern demarcation - these terms should only be used in as such in contemporary thought. We live in a global society and distinctions between the two are more or less outmoded, particularly in reference to the post-war Americanisation of many Asian countries.

Wabi-Sabi is an expressive way of life, but it is by no means exclusive to Japan, its sentiments are shared by humans regardless of geography and cultural boundaries. In relation to aesthetics alone, Wabi-Sabi has influenced the way beauty (beauty being the central enigma in art) is perceived in the East as much as classical Grecian culture in the West. Beauty as serene without added grandeur and the resonance of melancholic expression, artistic or otherwise, are universal sensibility albeit to varying degrees in different cultures.

"'Greatness' exists in the inconspicuous and overlooked details. Wabi-Sabi represents the exact opposite of the Western ideal of beauty as something monumental, spectacular and enduring. Wabi-Sabi is not found in nature at the moment of bloom or lushness, but at the moment of inception or subsiding. Wabi-Sabi is not about gorgeous flowers, majestic trees or bold landscapes. Wabi-Sabi is about the minor and the hidden, the tentative and the ephemeral: things so subtle and evanescent they are invisible to the vulgar eye" (Koren, 1994:50)

In relation to an international post-industrialist generalised Modernism, the dominant aesthetic standard since the mid-20th century, Leonard Koren points out there are a few similarities between the two: 'both apply to all manner of manmade objects, spaces and designs; both are strong reactions against the dominant established sensibilities of their time (modernism against 19th-century classicism and eclecticism, wabi-sabi against the Chinese perfection and gorgeousness of 16th century); both eschew any decoration that is not integral to structure, both are abstract, nonrepresentational ideals of beauty, and both have readily identifiable surface characteristics (modernism being seamless, smooth and polished, wabi-sabi being earthy, irregular and variegated)' (Koren, 1994:25-29). Koren goes on to make a list of comparative differences between Modernism and Wabi-Sabi:

ModernismWabi-Sabi
Primarily Expressed in the public domainPrimarily Expressed in the private domain
Logical rational worldviewIntuitive worldview
AbsoluteRelative
Seeks universal prototypical solutionsSeeks personal idiosyncratic solution
Mass-produced / ModularOne-of-a-kind / Variable
Expresses faith in progressThere is no progress
Future-orientatedPresent-orientated
Believes in control of natureBelieves in fundamental uncontrollability of nature
Romanticises technologyRomantisices nature
People adapting to machinesPeople adapting to nature
Geometric organisation of formOrganic organisation of form
The box as metaphorThe bowl as metaphor
Manmade materialsNatural materials
Ostensibly slickOstensibly crude
Needs to be maintainedAccommodates degradation and attrition
Purity makes expression richerCorrosion and contamination makes expression richer
Solicits reduction of sensory informationSolicits the expansion of sensory information
Intolerant of ambiguity and contradictionComfortable with ambiguity and contradiction
Generally light and brightGenerally dark and dim
Function and utility are primary valuesFunction and utility are not so important
Perfect materiality is an idealPerfect immateriality is an ideal
EverlastingTo everything there is a season
(Koren, 1994:26-29)

In the West, there is an undeniable tendency to avoid ... speculation about our inevitable passing, yet the sentiments impermanence and appreciation of things wabi-sabi have found voice in many of the world's artistic expressions. People are often drawn to the melancholy suggested by things wabi-sabi without really questioning why...

"Where the Japanese people may have differed in the past is in the completeness of their devotion to all arts that embody the essential reference point of impermanence. Through their earnest endeavours in matters of the spirit, they have managed their artforms so that they are worthy reflections of the mystery that we know as life. Their dedication to paring away all that is necessary, of reaching the real heart of the matter..." (Juniper, 2003:147)

References:
Koren, Leonard (1994) Wabi-Sabi for Artists, Designers, Poets & Philosophers. California: Imperfect Publishing.
Juniper, Andrew (2003) Wabi Sabi: The Japanese Art of Japanese of Impermanence. Tuttle Publishing