(Let me point out at the very beginning that I am aware that Mozilla Prism is still in beta. This commentary is specifically based on Mozila Prism 0.8 for Mac OS X.)

I love the idea of Mozilla Prism.

As an avid user of Gmail and other web-based applications, I can see the usefulness of a stripped down version of Firefox that makes my web applications behave similarly to a desktop application. Additionally, since Prism runs in a separate process, I don't have to worry about Firefox crashes killing my Gmail session, or losing unsaved data from a Google Docs Document.

So, I'm very excited about using Prism, but unfortunately, it's just not quite ready for production yet. Here are the problems I've discovered so far. Keep in mind, these problems are specific to Mozilla Prism 0.8 on Mac OS X 10.4 (Tiger).

1. Only one copy of Prism can be open at a time.
   This is the deal breaker for me. Unfortunately, I have more than one web application that I need open at a time, and the allure of Prism is dulled if I can't do that.
2. Why do I need to resize every time!
   Every time I open an application in Prism, the window size has been reset to the default. Unfortunately, the default size is not perfect for me, so I am forced to resize. Windows spawned by a running Prism process do not appear to inherent the parent's size.
3. Why not use the application's FAVICON if available?
   I believe this one is already on the upcoming feature list, so this is really just registering my annoyance. At the moment, all Prism shortcuts use the blue "world" icon. This is replaceable via Mac OS X's normal icon changing methods.

As I mentioned in the list, the inability to open multiple Prism applications, makes Prism unworkable for me. The other issues I could live with easily. It's worth noting that Mac users do have a working application that probably already fits the bill: Fluid.