Another option, in case you are not aware, is PDI glass. It is what I opted to go with on both my ST:Pro and MMr.
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LoginSame price, I think. Difference may be minimal, I don't know. Don't think I've seen Invisiglass in person to make a comparison. All I know is the difference it made on my machines is amazing, and I could never go back.
The PDI is a bit thicker than the default glass, and don't know how it compares to Invisaglass. It does make it a bit tighter fit on the machine. I don't really mind though since I'm not pulling it on/off that often anyway. But something to think about.