Short story here. I am not going to pour over their S-1 form to find interesting tidbits, others will do that, and are paid to do so.
They are the first of several, though I had thought that Dell would acquire them before they hit IPO. I am guessing that the combination of the price for them, plus the EMC acquisition stopped this conversation. So now Nutanix is going to IPO.
Nutanix is a software stack upon generic hardware. The hardware is usually lacklustre (original appliances being low/midrange supermicro gear, “newer” appliances being mostly Dell boxen).
Real hyperconvergence is hardware designed with as few barriers as possible to data motion and performance. pseudo-HCI is a software stack upon generic hardware. HC systems require very high performance, and very few barriers throughout the entire stack … you simply cannot slap random software on random hardware and hope for the best, as the architectural elements you ignored will usually be the first ones to bite you hard when you start pressing this under load.
Hyperconverged is well architected hardware and software. Anything else is marketing.