I've used Share This, and Onlywire...
And I've had virtually no results with either
A lot of these buttons are great for tech blogs, because their audience is tech savvy and probably very familiar with digg, stumbleupon, twitter, etc.
I'm still trying to find the best way to find or create readers who are into personal development, meditation, spirituality, and are familiar with using social bookmarking.
keep smiling,
Ben