title: Pros and cons of MS Ajax vs. jQuery in an ASP.NET MVC app?
body: <p>Now that RC1 is out I need to decide once and for all whether to use MS Ajax libraries or just jQuery for AJAX requests. The application is a new application. Essentially the way I'll decide is whether or not i get any <strong>significant</strong> benefit from the Microsoft libraries that I wouldn't get from jQuery. I already HAVE jQuery loading and I am concerned about the extra overhead of file size more than anything.</p>
  
  <p>As far as I'm aware -- the only benefit really is that there are helpers like <code>Ajax.BeginForm</code>, but perhaps these will work with jQuery at some point anyway? I was also told today by a government employee friend of mine that MS Ajax library has a LOT of bugs in it - which concerns me.</p>
  
  <p>With Microsoft now having officially <a href="http://weblogs.asp.net/scottgu/archive/2008/09/28/jquery-and-microsoft.aspx" rel="noreferrer">befriended jQuery</a> I wouldn't be too worried about them doing anything in future to leave jQuery in the dust by enhancing their own libraries.</p>
  
  <p>I really don't know a whole lot about exactly what MS Ajax actually does for me. Are there certain pros and cons. Or is it just 90% bloat to support 'update panel' ?</p>
  
  <p>I also find it very interesting that the <a href="http://www.manning.com/palermo/" rel="noreferrer">ASP.NET MVC in Action</a> book just skips over the MS Ajax libraries and jumps straight into jQuery :</p>
  
  <blockquote>
    <p>In this chapter the reader will
    examine how the ajax technique is
    applied to ASP.NET MVC in a more
    seamless way than with Web Forms. The
    reader will see how to leverage an
    increasingly popular, lightweight
    javascript library called jQuery.</p>
    
    <p>(from <a href="http://www.manning.com/palermo/palermo_meapch9_sample.pdf" rel="noreferrer">free sample</a> chapter on AJAX)</p>
  </blockquote>
  
  <p>Would very much appreciate hearing from anyone about their experiences workin with both, expecially on the following additional questions :</p>
  
  <ul>
  <li>is it easy to convert code between the two libraries - assuming relatively simple ajax requirements ? </li>
  <li>is debugging notably better or faster in either library</li>
  <li>anybody know how ASP.NET 4.0 is progressing and any announced plans for the AJAX library that might be beneficial to MVC?</li>
  <li>what in a nutshell could MS AJAX do for an MVC app beyond sending requests and sticking the response in a DIV? </li>
  <li>how do i do the equivalent of <code>Ajax.BeginForm(...)</code> and use jQuery ?</li>
  <li>what was your deal killer one way or the other?</li>
  <li>what are most people out there using?</li>
  </ul>