Direct Hits 2011 vs '4th Edition'

<p>Hi guys,</p>

<p>I just went through both Volume 1 and 2 of Direct Hits (2011 Edition).
I noticed that there is a newer version (4th edition).</p>

<p>Is this book different than its predecessor? Should I get it?</p>

<p>Also, what additional books should I use to study for vocabulary?
I went through 1) Word Smart I 2) Direct Hits (I, II)...</p>