I have a test mule PC (600 MHz PIII) running RedHat Linux 9 (Shrike) and Domino 6.5.4. I downloaded the 7.0 Beta 4 today and attempted a straight upgrade (didn't read instructions...). It went fairly well, and I noticed that the installer now has a text-based "status bar" showing the completion percent - which was a pretty handy addition.
I was told by the installer that Domino does not support Shrike. Guess I'll have to peruse the readme and see what distro I need. Hopefully it's at LinuxISO.org.
As a side note, I had G Simmons (not gene!) upgrade from Notes 6.5.4 to 7.0 Beta 4. He instantly noticed a performance improvement in navigating his 6.5.4 mail file. Hopefully we'll see others giving the same feedback. I'm considering SmartUpgrading our IT department although I can't personally upgrade because of Development. I'm curious to see if I get any more positive feedback. Just today our PC Support manager was asking me if there had been improvements made to the DWA client in 6.5.4. I told him that there were many improvements and he said that he could definitely tell when accessing via his cable modem.
Scalability and ROI is what we've been seeing with the latest releases of Notes and Domino. There are supposed to be some performance enhancements with the 7.0 Domino iSeries code as well. I love a product that will allow you to leverage current hardware and software investments. I won't mention Exchange upgrades (they call it Exchange because you exchange out your current server and OS platforms for a newer investment...)