Try contacting LMS, they'll probably let you borrow it for a month if you are a serious customer.
As to what it is, well, if you don't know why do you want to evaluate it? It is a powerful signal acquisition and analysis suite, widely used in the automotive industry, for things like modal analysis, rotating machinery analysis, noise path analysis etc etc etc.
I would add that it is probably the most expensive of the alternatives, and the annual licensing fees are in due proportion. On the other hand it definitely works, is stable, easy to use (though frankly if you've used one of these programs there is not much difficulty in using another) and is powerful, at least under Unix. Cheers
Greg Locock