I use an Instron machine almost daily at work. I think MTS just stands for "Materials Testing System". The company makes lots of different machines, but the most commonly used ones are the standard compression / tensile testing units, which is probably what the job description is referring to. These pretty much all do the same thing, although you can get different machine configurations (sizes and load ratings, single / dual column, etc), software packages, and numerous specialized grips, which would depend on what you are using the machine for.
Our particular machine is a dual-column machine rated at 10,000 lbs IIRC. It's 17 years old and was retrofit some years ago to output to a computer. Learning curve on these things is almost nonexistent - the hardest part is probably getting into the software and creating test methods. Which basically involves setting the test parameters, automatic stop conditions, and outputs.
I've actually spent a bit of time researching new ones, as ours seems to be flaking out a bit and Instron tells us that parts are no longer available for it.