I've been running on a Nutanix CE install for about a month now. With the November release they added some much needed GUI controls for the image service. You can now import ISOs for install images, without having to fiddle with CLI stuff.
I've had virtually no problems, and the VMs are performing well. If there's one complaint I have with this solution it's that the baseline memory utilization is high. I couldn't reduce the CVM's to less than 8GB each without running into serious problems with the cluster. Plus, there seems to be a missing 3GB per host. I'm assuming this is what the actual CE and KVM host requires, but that seems high. I know I can run VMWare ESXi in less than 1GB per host. So, 11GB per host is used up right from the start. Since I'm running this on a shoestring budget with 16GB per host, I really only have 5GB available for VMs. That kinda sucks.
On the upside, the CVM's at 8GB work fine and the IO performance is pretty amazing. I've seen upwards of 1600 IOPS at times. This is basically a single consumer grade 240GB SSD in each host for the primary tier and 640GB HDD for the secondary tier. I don't think I'm even using the secondary yet. 3 hosts at varying levels of i5 CPU's, but none of them current gen.
I'm pretty happy with this and I'm looking forward to seeing what Nutanix does next.