Fusion and VMWare Server compatibility

I created a guest Windows 2000 Pro SP4 using Fusion build 36932. I then tried to open this guest OS in VMWare Server version 1.0.1. I got an error message saying that this guest OS was created by "Fusion that has more features" and the "boot" did not proceed any further. However, Fusion build 36932 has no problem opening a guest OS (FreeNAS appliance) which I assumed was built under VMWare Server 1.0.1. So at the time of this writing, Fusion is better than VMWare Server in terms of being able to open guest OSes. The current build of Fusion however does not support several features that VMWare Server supports, namely Snapshot and ISO mounting. I do not know how well does VMware Workstation v 5.5.3 or v6 beta and Player supports guest OSes created by Fusion. Frankly I cannot keep up with all this neck-breaking pace development of virtual machines from VMWare. :-) But I love it.