It does work well on bird droppings. In my experience it breaks down the dirt as opposed to encapsulating it like QEW does. If you spray some on a bird bomb and watch it for a few seconds it will literally break it apart and you can just wipe it away. Poorboys also has a bird bomb remover which I have not used which is supposedly heavier duty S&W. I feel comfortable using S&W to remove road film after a touchless wash, to remove puddle splashes, if you hit a little rain squall where you have some water spotting on top of driving film S&W could handle that (these are all scenarios I wouldn't use a QD for) It actually works well on windows. Good for cleaning up bugs that you've just hit, I always carry a little bottle and an MF in the car for bird bombs and bug hits.
I would not however use S&W to clean the car after it has been driven in inclement weather or around any kind of abrasive fallout for a period of several days or a week, to me this is where the difference between QEW and S&W exists.
I really wouldn't rely on S&W to wash your car unless you get no rain and you're S&W'ing every 2 days or so. BUT, its expensive so even then you'd have to weigh the cost benefits with QEW.
I use S&W in a Zep professional spray bottle filled up to about 35 ounces. Now, there's what 130 ounces in a gallon, meaning S&W costs $.28 an ounce IF you buy it by the gallon. Now, I use between 5-10 ounces to do an entire car, be it after the touchless or if I've hit a rain squall or something, meaning it costs me $1.40-$2.80 to spray the entire car down with S&W. Now, If I did that every 2-3 days instead of washing thats $4.20 a week, $16.80 a month ASSUMING you can limit your use to 5 ounces, and I would be hard pressed to do that if the car was dirty with a week's grime.
Now, what does a gallon of QEW cost $25? Makes it $.19 an ounce, you use one ounce to wash an entire car, so one wash costs you $.16 instead of potentially $2.80. If you QEW every week, you're spending $.76 a month to wash the car.
Financially, there's no contest and really, the QEW is just as easy as S&W'ing after you've mixed it up.
When the weather gets better and I run my car through the touchless I'll tell you what, I'll mix up a spray bottle with the normal dillution of QEW and use it instead of the S&W and tell you what I think.
