I'm looking for suggestions on Flash realtime servers. Currently, we use a combination of Moock's [Unity](http://www.moock.org/unity/) and [Red5](http://osflash.org/red5), but there are a couple problems. First, we are moving to AS3, and Unity only supports AS2. Secondly, Red5 is pretty flaky for us, we'd prefer something more stable. We can't use the official Flash Media Server, it's a bit out of our price range (starts at [$4,500](http://www.adobe.com/products/flashmediaserver/compare/) for a single license).

So far, I've found two servers that look like they would meet my needs, [ElectroServer](http://www.electro-server.com/overview.aspx) and [Wowza Media Server](http://www.wowzamedia.com/products.html). Does anyone have any experience with these, or have any other servers to suggest? The main features I'm looking for:

1. Stable
2. AS3 support in client libraries
3. Can extend server-side (with Java or other languages)
4. Supports real time audio/video from flash clients (eg webcams)
5. (not required, but very helpful) Some method of communicating when all traffic except HTTP or HTTPS is blocked. Eg RTMPT (tunnels RTMP over HTTP) support or similar.
6. Reasonable performance, I'd like to get at least a couple hundred users connected without killing a server.