Kevin, how could you write one of the most useful tools in a Flash/Flex developer's toolset but forget to tell anyone about it? It was by pure chance that I stumbled upon your excellent ServiceCapture tool in Josh Dura's blog post, even though I had been searching for an HTTP monitor/bandwidth throttler/AMF debugger on Google for ages.
It bears repeating: ServiceCapture is a lightweight, usable HTTP Proxy, HTTP Monitor, Web Debugging Tool and, most importantly, Bandwidth Throttle and AMF Debugger. (Google, are you listening?) 
I can't even begin to thank you for saving me from the one program that does come up in Google searches and has apparently been quite-widely blogged about in the Flash community: Charles.
Charles is one of the worst applications I have ever had the pleasure of using. I'm talking about teeth-extraction-without-anasthetic bad. I'm talking you-want-to-gnaw-your-own-arm-off bad: An unusably slow interface that rewards your patience with an endless barrage of shareware nag windows featuring the image of a hideous white jug. I completely understand the need to get paid for your software but, guess what? Pissing off your potential customers is not the way to do it! Not to mention that Charles costs $50 whereas ServiceCapture is $34.99.
The choice is clear: We're going to be using ServiceCapture
The ServiceCapture: A Dream Come True article by Aral Balkan, unless otherwise expressly stated, is licensed under a Creative Commons Attribution-Noncommercial 2.0 UK: England License.
just a bummer ServiceCapture is windows only. Even though it’s developed in Java.
Charles has a much cleaner default output, and ServiceCapture seemed to cause issues with Entourage and some other network services. Yeah, Charles is $50, but I found Charles to be the better fit. Charles offers free lifetime updates and I’m not sure if ServiceCapture matches the deal. If not, the total investment may be moot on the next release of ServiceCapture.
I don’t agree at all!
Yes, Charles shareware version is not very pleasant to work with, I agree. But judging a program only by it’s shareware restrictions is wrong.
After trying both I found Charles far more superior!
I couldn’t setup amf over https on servicecapture.
service capture can’t display the raw text of amf calls.
Charles’ interface is not at all slow, and easier to read, with more
display options.
Charles’ browser installation is a lot smoother.
I would never go back to service capture.