comparative performance of Unix machines

This is not an easy thing to do as many factors affect performance.  MIPS is particularly unreliable as a performance indicator anymore.  Much of the problem is the definition of an "instruction" in the MIPS calculation.  Several 3rd party performance tools have been developed with names line Whetstone, Dhrystone, Linpack, and others.  Each of these has different areas which they tend to measure.  More recently, the IEEE has become involved and developed a set of standardized benchmarks which try to measure real system level performance issues.  These are called SPECmarks.  You will often see the names, SPECint95 and SPECfp95 quoted in system advertisements.  These two are the most common and measure the integer performance and floating point performance respectively.

Just a final comment.  I'd strongly caution you about putting too much stock in ANY benchmark as a determination of system performance.  So much depends on YOUR application and YOU environment that the only reliable method of determining performance is to run one of these workstations in your environment with your intended application and see how it performs.

jhance's answer was very good indeed, but not quite what I was looking for; so I'll refine my question. I'm looking for a specific article, study, report etc. that compares the workstations mentioned above (HP C-200, Sun Ultrasparc 2), or a link to such report. If such info is not available, I would like to find out where exactly I could get a measuring tool