What do you like best?
Helion Eucalyptus 's AWS compatibility is its biggest attraction for those dwindling use cases where a private cloud might make sense. This might generally be as a transition phase where a company has a legacy infrastructure of data centers with heavy investment ans also an investment in underused compute and storage.
The unused compute and storage capacity can be used to build a target IaaS infrastructure for proof of concept. This can also be useful if the security, compliance, and audit staff aren't yet comfortable with sensitive data except on site.
What do you dislike?
AWS, Azure, and Google compute are now so developed that it probably makes more sense to avoid private cloud altogether and just concentrate resources on moving legacy applications to one or more of these providers. Then, while there's still a market, the company's data centers could be sold.
Helion assumes that compute and storage infrastructure is capable of the target application workloads. If additional investment was needed, it would typically be a 3 to 5 year CapEx, which seems like a waste in today's environment. For full production testing with loads approximating peak usage, it's not feasible to use a few trial, small instances and associated storage and networking.
Recommendations to others considering the product
I'd look carefully at the total cost of operating a private cloud. I would not buy additional compute and store or do additional electrical/mechanical (HVAC) investment in current, owned data centers. In fact, if required to use this product for some specific use case, I would operate Helion/Eucalyptus only in multiple well connected co-location facilities for resilience and to allow exercising the multiple site infrastructure scenarios needed for a decent private cloud.
What business problems are you solving with the product? What benefits have you realized?
Typical medium to large enterprise business applications, generally not cloud compliant, so "legacy." They generally need to be refreshed or replaced as applications suitable for IaaS scale out and component disruption.
In the past Helion offered the ability to do small, "toy" proof of concepts using on premises compute/storage infrastructure. With the range of AWS, Azure, and Google IaaS offerings, as well as support from many vendors, there is less benefit to Helion and private cloud more generally.