Well if it were true zero tds then there wouldn't be any difference.
Think about no dissolved solids is no dissolved solids however its achieved.
However we are only measuring parts per million. So the water still has dissolved solids.
So in theory I guess there is probably a difference in composition between the two. How that affects window cleaning I have no idea.
But if you can get zero ppm from an R O you are doing very well I've never heard of that before.
I would d. I it regardless to be on the safe side
I know some (idiots?) use straight R. O water at like 6ppm but for me I only belive in using as pure as we can so 0 ppm.
You define idiot as someone who does not want to pay £80 for a bag of resin.
My RO water is usually 003-004 so I see no point in using resin. I think the highest it has gone to is 007 before I changed the pre-filter.
It is quite possible purifying water further through resin improves its cleaning ability, otherwise why would Ionics market their parts per billion system.
Personally for me I find RO water works well enough.