title: clk'event vs rising_edge()
body: <p>I had always used this for detecting a rising edge:</p>
  
  <p><code>if (clk'event and clk='1') then</code></p>
  
  <p>but this can also be used:</p>
  
  <p><code>if rising_edge(clk) then</code></p>
  
  <p>Reading <a href="http://vhdlguru.blogspot.com/2010/04/difference-between-risingedgeclk-and.html" rel="noreferrer">this post</a>, <code>rising_edge(clk)</code> is recommended, but there is also <a href="http://vhdlguru.blogspot.com.es/2010/04/difference-between-risingedgeclk-and.html?showComment=1359749429783#c5987704624802319840" rel="noreferrer">a comment</a> indicating that <code>rising_edge(clk)</code> could lead to wrong behaviour.</p>
  
  <p>I can't decide which one to choose for the future, going on with <code>(clk'event and clk='1')</code> or adopting <code>rising_edge(clk)</code>.</p>
  
  <p>Any real-world expereince on these two? Any preferences?</p>
  
  <p>Thanks!</p>