<p>What's the best .NET PDF editing library available, and why?</p>

<p>It needs to be used on an IIS web-server.
Specifically, I need to edit a PDF which was generated by reporting services.</p>

<p>Factors I'm interested in:</p>

<ol>
<li>Speed</li>
<li>Memory Consumption</li>
<li>Price</li>
<li>Quality of documentation</li>
<li>Library stability</li>
<li>Size of library</li>
<li>Whatever else you think is important</li>
</ol>

I don't know if it's the best, but I use
PDF-Writer.NET
, for which I paid $89. I have used it in several production applications. I like it because it's easy to set up and use, and it doesn't require a lot of coding, which makes it easier for new developers to ramp up on it.
Before that I was hacking together PDFs using an open source library and the Acrobat interop DLLs. That was rough.