What answers do you expect when you ask at Mercedes about VW cars ?
Same here ...
You will probably hear:
VMware is the only product that can handle really large environments
VMware is the product with the best admin tools
VMware is the most reliable product
VMware is the fastest product
If you are lucky you may hear:
XEN may be cheaper
XEN maybe good enough for your small environment - probably you can smell lots of arrogance or pity in this replies
We use VMware because we need a support contract with an established company - everything that smells like OpenSource is unacceptable
Xen or XenServer can't handle large environments? How about AWS or other cloud giants? They using Xen.
Citrix is not an established company?
We see VMware on AWS.
I thought AWS use a customizied KVM version rather than XEN(they used XEN in the past)
The problem was 10-12 Years ago. XEN doesnt come with alot of APIs for backup and automatization and so there wasnt that much 3rd. Party stuff around. VMware offers a lot of APIs from the beginning and so a large ecosystems of partners joined.
Also finding someone with vSphere Skills is a lot of easier as one for XEN. 10 Years ago we have both in the DC (ESX and XenSource) and today its ESXi and Hyper-V(ROBO only). I have to support a tripple digit of VMware customers... and one XEN (which currently migration to vSphere).
If you read my post carefully you will see that i dont mentioned any technical feature or named a product which is better than the other.
Indeed, AWS uses their own custom heavily modified version of KVM (various articles to be found on this), and even when they used Xen they had their own flavor of it. Not giving my opinion on Xen or KVM, considering I work for VMware.
You wrong. AWS using Xen and KVM and it will remove both of them in the future. Amazon will use its own hypervisor(Nitro). How about Oracle?
People migrate from Xen or other platforms to VMware because they like GUI. Xen has orchestration(https://xen-orchestra.com/#!/xo-home).
I used both of them and Citrix XenServer in my opinion had a better performance.
Some companies like KVM because it is Type-2 and convert Linux to Type-1. When you use KVM, then it mean that you don't need a real virtualization.