i just want to know the pros and cons, from performance and managability point of view. liek, e.g. ESXi only gives ssh access and you cannot install any software on the Hypervisor, it WILL install but on reboot will be wiped out. etc etc
VMWare Workstation is a desktop product for testing and developing and not meant to run servers for production use.
- Needs a complete X11 environment
- Needs a full operating system as basis
- If you happen to kill your X server for some reason, VMware dies as well
- Is more resource-intensive than ESXi
All in all, if you want a production system, VMWare workstation is not an option (IMHO).
It would make more sense to compare i.e. Xen or KVM on Ubuntu to ESXi, because that approach is more comparable.
VMware's Workstation and ESXi are designed for completely different purposes. I use both every day, so will give a breakdown of how I use them. What you should use will depend entirely on what you're trying to do.
ESXi is a thin "bare-metal" hypervisor, designed to be installed directly on server systems with zero direct user interaction. I've got a number of nodes with ESXi installed which run a complete development and staging environment. I can run multiple webserver and database server VMs on these nodes and manage the whole thing remotely over a network.
Workstation is a hypervisor that runs on top of an existing OS (I think Windows and Linux are supported). I'm currently use this to simulate a small test environment to work out some tricky AD configurations. The performance isn't as good as running the VMs on ESXi, but has the key advantage that I can pick my laptop up and have the entire test environment come with me.
In short, Workstation is useful for trying things out, and lets you easily get up and running with a small test environment, but don't expect production-level performance and reliability. ESX/ESXi are more designed for datacenter use where you want the flexibility of virtualisation but with maximum reliability and performance.
ESXi turns your computer into a computing appliance and all your VMs run independantly. ESXi will is a lighter-weight virtualization environment. However you don't have a workstation environment and you will therefore need another computer to manage it and use the VMs from.
With Ubuntu you have a full workstation environment. This will make the computer a lot easier to work with when you are sitting at it. On the other hand VMware Workstation doesn't take as full advantage of your potential hardware. It isn't designed for production use -- you can set VMs to start automatically with the base OS, but it really isn't designed to work that way.
Bottom line: if you have only one computer, and need a desktop environment, and are just playing -- VMware Workstation is adequate.
If you are looking at a production environment -- ESXi.