title: What are the Best Components of Boost?
body: <p>I've been browsing revision 1.38.0 of the Boost libraries, in an attempt to decide if there are enough jewels there to justify negotiating my company's external software approval process. In the course of writing test programs and reading the documents, I've reached a couple conclusions</p>
  
  <ul>
  <li>of course, not everything in Boost will ever be of use in my engineering group</li>
  <li>more importantly, some of these libraries seem more polished than others</li>
  </ul>
  
  <p>In fact, some libraries seem a bit toy-like to me.</p>
  
  <p>There are a number of fairly accessible libraries that I can see putting to use after only a short period of investigation, such as <em>boost::variant</em> (I really like the <em>visitor</em> component and the fact that the compiler barfs if a visitor lacks an operator for one of the variant types). I'd use <em>boost::shared_ptr</em> except for the fact that our group already has a set of smart pointer types.</p>
  
  <p>So based on the broad experience of Stack Overflow users, which Boost libraries</p>
  
  <ul>
  <li>have high quality?</li>
  <li>are more than toys?</li>
  <li>are there any which have a high entry barrier but which are well worth learning?</li>
  </ul>
  
  <p>Note that this is a somewhat different question than that posed in <a href="https://stackoverflow.com/questions/569198/boost-considered-harmful">Boost considered harmful?</a></p>
  
  <p>P.S. - Has one of the answers (from litb) been deleted? I can't see it here, and only an excerpt on my user page...</p>