We're asked about this fairly regularly, so I thought it was about time I posted up our position on it here. There are two main reasons:

• The auto-update means that we can roll out improvements to all users. So far, that's meant the occasional bug fix, but for some time we've been working on some big improvements. These include new functionality, along with fixes for a lot of the bug reports we've received. We aim to get this out early next year, and everybody will receive the benefit of this update.
• Support: having only one version in the wild makes supporting .NET Reflector, which is extremely popular, a much more manageable task. This really goes back to the first reason: if we fix a problem everybody gets the fix and hopefully everybody's happy.

We are always looking at making things better though so, if you've had a problem with the auto-update, please let us know about it and we'll see what we can do to improve matters.

On a side-note, we are occasionally asked what we use for the auto-update function, and whether people can use this in their own applications. Unfortunately the answer to this is no, because it's our own proprietary code, but if you are after this kind of functionality, I'd recommend Microsoft's own ClickOnce deployment, which ships with the .NET framework:

http://msdn.microsoft.com/en-us/library/wh45kb66.aspx