I get a lot of questions regarding whether to use ESX or ESXi. I have been working with VMware for a long time and have loved using ESX because of the easy accessible service console. My recommendations so far have been:
New to VMware: Use ESXi – you have never used the service console and won’t miss it.
Already using VMware: Use ESX if you have special scripts and 3rd party applications that relies on the SC.
Last week I delivered my first vSphere Design Workshop. Some of the course content was very direct regarding this matter. Actually this is the first place I have seen it in writing from VMware.
§First choice is ESXi Embedded, whenever possible.
•ESXi is the future.
VMware has announced its intention to eventually replace ESX with ESXi.
§Design the management infrastructure to support VMware® ESXi, even if deploying VMware ESX™.
•Limit the use of service console–based command-line management and monitoring agents.
•Develop ESXi management techniques now because ESX will eventually be phased out.