Sound Forge Audio Studio Vocal Eraser

Basically I’m considering buying this program so I can make my own acapellas. I realise it takes a while to line it up and what not. But then I read on the Sony website that it has a Vocal Extractor. This is what it says:

"Sound Forge Audio Studio 9 software includes the Vocal Eraser plug-in. Easily remove vocals from most recordings or isolate vocals. You can also use this plug-in to extract vocals from songs for remixing. The Vocal Eraser plug-in contains presets for various recording situations."

Does anyone have this software? If so, please tell me what it is like and how the acapellas turn out! I don’t wanna spend £35 on something that isn’t all that good. Apart from this program, are their any other plugins/programs that can ‘isolate’ vocals? I need to know because I’ve been asked to make some remixes and I don’t know how it is possible to make an acapella with just the track on it’s own! The songs I need acapellas for are kinda old and aren’t that popular so the chances of me finding them anywhere on the internet is slim. If anyone has any suggestions as to what I could do, I would be very grateful!