I've not had any time to try out Jaxer yet, but the idea of a single platform for both client and server-side processing sounds good.
On trying to get started, though, one problem I encountered was that the installation instructions on Aptana's site didn't quite get Jaxer running on my default Ubuntu 8.04 install. The reason seems to be the built-in Apache trying to load an external library from
/usr/lib which doesn't exist.
The library in question is libexpat.so.0; however, there is a libexpat.so.1.5.2 installed! You can check this by running:
Creating a link to this file in /usr/lib with:
bash$ ln -s libexpat.so.1.5.2 /usr/bin/libexpat.so.0```
seems to have got Jaxer running and the server status looks good. If you're having trouble getting a Jaxer server running on the latest Ubuntu, this might be worth giving a go.