The KB article is a bit confusing, but maybe it was just me…
The key to understanding is that the “Compatible with” column applies to the host device, meaning the device directly connected to Drobo. The client device in a shared network situation (ie, through DroboShare) doesn’t matter as long as it supports Samba.
If you’re only using DroboShare, then it doesn’t matter. The DroboShare is the host device. I chose the newer NTFS with 16TB thin provisioning since I might connect it directly to my Vista or Win2K3 server at some point. Beyond the DroboShare, any DroboShare-compatible client computer can access its data. I can access my 3.5TB Drobo fine from my 32-bit Windows XP Pro laptop, because it’s really accessing the DroboShare, and not directly accessing the Drobo.
If you are going to connect the Drobo directly to a computer, then that’s where the choice must be made depending on the OS of the client computers that will be connected (directly) to the Drobo.
Hope that helps!