This was used in an organisation which I was working for, using a client-server architecture. This led to a more consistent environment and prevented *snowflake* desktops, which could be hard to diagnose issues on and provide support for. This also increased security and ultimately ended up saving a significant amount money for the company.
Pros
Standardisation where provisioning the environment became repeatable and predictable.
Easier debugging and understanding the client system.
Improved security and centrally managed.
Cons
Ran into a regression when updating firmware for IGEL
Desktop froze and became non responsive on a few occasions.
Server crashed and took down all the clients in the Thin setup.
Likelihood to Recommend
Well suited for very large organisations with a wide variety of departments.
Less useful for a single group of developers where the command line is mostly used.
It's currently being used across the organization - it includes all the enterprise-grade features for a less overall TCO as compared to something like VMware's offerings. It's easy to use, manage, and provision and has rock-solid reliability. It's backed with the best support in the industry and uses KVM Virtualization under the hood which is used all throughout the industry by some of the top names (AWS and Rackspace to name a couple).
Pros
Base licensing includes H/A and Live Migration features (you don't have to pay extra for them like VMware).
It's all completely managed through a WebUI - no fat client you have to install.
Very easy to use, manage, provision, and upgrade.
Cons
It's definitely come a long ways from what it used to be and is certainly a lot easier - the initial setup/configuration used to be quite difficult but really isn't anymore.
Better support and third-party integration for backup, snapshots, and restore of VMs like VEEAM for VMware - this is my only complaint. There are companies that offer solutions for RHEV however they're very limited and can be pricey.
I think some improvement can be made for deploying micro and cloud services through RHEV.
Likelihood to Recommend
I believe it's an excellent solution for any scenario which requires virtualization. The only scenario where it might not be the best solution would be in building out a cloud infrastructure - you could certainly integrate RHEV for something like that but I think that either OpenStack or CloudStack might be a better solution for building cloud environments.
I am working as a Consultant, so I usually advise other companies in terms of virtualization solutions and implement them.
RHEV is usually used at our customers for providing an open-source based virtualization stack which is very similar to virtualization systems they already have (e.g. libvirt and KVM nodes). Therefore the learning curve is really low when RHEV is introduced to them.
Pros
Providing Virtualization services
Migrating VMs from other virtualization stacks to RHEV
Providing open-source based VDI
Providing a GUI for KVM
Providing HA virtualization
Cons
Native Ceph implementation is still missing
Only few software-defined Storage solutions are supported as storage backends
VM management (with virtual hardware, first boot etc.) is a bit fiddly
Likelihood to Recommend
Red Hat Enterprise Virtualization is well suited for IT departments which use open-source software already and want to rely on an enterprise virtualization solution which is very similar to the tools they already know.
In addition, RHEV fits in very well to environments already containing other products from Red Hat.
IT departmens with high performance needs should avoid RHEV in some scenarios.
