I use react inline styles in some situations where it's appropriate. on large tables or SVG (eg. with zillions of styled circles) there will be issues.
if you are sending HTML from a server with inline-styles then you will have much bigger problems with bandwidth.
This is where tachyon and basscss can provide a clean way for the day to day simple styling tasks like "needs more padding here" "make that title bigger there" without writing up stylesheets with repetitive margin, float, etc. for every single view in your app or every page on your website.
