Last week I delivered another 3 days vSphere Manage for Performance course. The course was developed for ESX 4.0 but I felt confident that ESXi 4.1 would do the job.
One thing I really like about ESXi 4.1 is the options to enable SSH to the host from the vSphere client. (Configuration, Security Profile, Properties)
When you get SSH enabled you have direct access to the host. When you use your favorite SSH client (Mine is putty) and logon to the host you will have access to ESXTOP and vscsistats. Thats right, finally these two great tools is bundled with the default installation.