Still, for those who have a nicely working inkjet printer, inksaver is really effective. Not only it reduces the quantity of ink used, but I find it improves the quality, when using low grade paper : less ink = less smear (if that's the right word). So I would definitely like to have a vista version, long time promised by the publisher (the developer has probably left the company...). I also found no real equivalent.
I never tried installing it on Vista, because of what the publisher says :
"Any PC running Windows® 2000, XP Home or XP Professional (if are using Windows Me or Windows 98 click here). Note: InkSaver does not currently support Windows Vista; we are in the planning stages for an updated version of InkSaver to support this new OS."