I have had good results with "Invisible Glass", too. GM parts dep't also sells a glass cleaner (GM brand) that really does a good job, believe it or not! (Not sure if it voids the Mercedes warranty
)
Are you sure it's the cleaner? Are you using clean cotton towels with not too much fabric softener? Also, I sometimes find it necessary to add a little water to my Windex to allow it to be wiped up before it evaporates, especially in summer. I use the good old Windex with good results.
-Tom