As with any benchmark, it's a perfect indication of how well a processor will perform on that benchmark. Beyond that - it depends.

You can read all of the details here and dig into individual test results on individual chips if you need to. As with any composite benchmark, 75% better doesn't mean it is 75% better on everything. Are you rendering graphics, processing video, playing video games? You may be able to find one specific test that is better aligned and will give you a better indication.

But this is a site that I generally use for comparison. IMHO, it's as good as anything else out there for an "overall" comparison, as long as you use it knowing what it is and isn't.