1) Easier way of segmenting the resources.
2) Host profiles - Template to build hosts in minutes.
3) Performance and Graphs - Easy to monitor the hosts
4) Vmotion - In essence, this technique helps you to move a live server between hosts without any downtime.
5) Robust Management Tools
6) Cost saving
7) Advanced memory management - The memory unused in the hosts can be reclaimed and used effectively.
8) High availability
Room for Improvement:
The major disadvantage that i can think off is that we have to pay for all the features to be available. Virtualization has made datacentre operations easier. As a sysadmin, managing multiple hosts is more simpler and flexible with the vmware ESXi. Running multiple hosts, operating systems on a single host makes it more efficient and saves costs. ESXi also allows you to pool the resources of several machines effectively, thereby helping to run the application smoothly without hassles.
This gives the technology lovers an opportunity to do all the things they want or need to do at the same time.