So, for the record, here's my take on it:
- The Mac OS X client (version 1.5 and previous) is one of the absolute worst Mac applications I have ever had the displeasure of running. I will freely grant that 2.0 has improved, even if it does not feel particularly Mac-like.
- Even prior to neatx, the server was a needless hassle to install and manage anywhere (even after FreeNX appeared), and mucks about entirely too much with X11. I can apt-get or yum VNC on any Linux box and get it working in a couple of minutes. And yes, I am aware of the freenx package in Fedora Core 5 extras, and of the peculiar need to nxserver --adduser and nxserver --passwd whomever feels like using NX.
- The client is mostly the same: I can fire up a 260KB VNC executable from a pen drive (or use the built-in Remote Desktop client) in any Windows machine on the planet, and it's nearly as easy to get vncviewer, rdesktop or a Mac OS X binary on other machines. Or, god forbid, just use plain old X11 forwarding...
- It has (for me) no significant advantages over RDP or VNC (and by VNC I mean optimized VNC protocols) atop SSH.
I especially like returning to a VNC workspace and finding it just as it was before I disconnected, and routinely use both VNC and RDP over UMTS links without any performance issues. Even if NX now has support for persistent sessions, I find it an unnecessary hassle.
My only real gripe with VNC is that current Mac OS X clients have very serious keyboard mapping issues that make it damn near impossible to code or do system administration tasks using a Portuguese keyboard.
Otherwise, I'll take it over NX any day.