Wfp does a good job most of the time. There are weather conditions especially if you live near the coast, that WFP can be dreadful.
I cleaned my windscreen this morning WFP, within 2 hours it was really filthy, and I was parked up the whole time. Strong onshore winds are a waste of time with WFP.
I don't know if it's the salt laden air, or stuff blowing around. My screen was not spotty there were dried rivulets of water all over it. I really think that DI water attracts salt. If I had cleaned trad, or dried it off with a blade I would not have had the problem.
To be fair, I don't get half the complaints WFP than I did trad, and I didn't get many then.
But WFP is not Gods gift all the time. Dai