The problem with React is its patent rider. React.js comes with a BSD license, but has a patent rider that gives you a license to React's patents. This sounds like a good thing, right? But this rider has a "strong retaliation clause" which says that if you make any sort of patent claim against Facebook this patent license automatically terminates. Which means Facebook can now sue you for patent infringement for using React. You may think this is no worse than not having a patent rider at all. But that's not the case. If there is no patent rider then there is an implicit grant which cannot be revoked.
If you work for a software company and your company has patents then keep in mind that by using React you are giving Facebook a free license to your entire patent portfolio.
If you work for a software company and your company has patents then keep in mind that by using React you are giving Facebook a free license to your entire patent portfolio.
More info on weak vs strong retaliation clauses: http://www.rosenlaw.com/lj9.htm