A close friend of mine came to work for me. I trained him decades ago at a different company. On the first day we worked together, I noticed he used a wagtail to do everything. I’d seen it on YouTube and thought it was interesting but hardly superior to my Sorbo. I asked him why he used it so much, and he said his carpal tunnel syndrome was getting so bad the wagtail was the only way he could reduce the repetitive motion. He also claimed to do short pole work twice as fast as a regular squeegee. He had a spare wagtail that he gave me. I tried it, failed miserably, and it sat in my bucket unused for six months. He finally decided to instruct me in its proper use.
He was right. The wagtail did save a great deal of time in the hands of a guy who knew how to use it. One trick he showed me was to roll the pole with my fingertips clockwise to the right, counterclockwise when squeegeeing left. The wagtail was especially effective when doing long, horizontal transoms and windows with curved tops. It can get behind desks and cabinets without having to angle the handle. It took me a lot of practice to become proficient with it; the learning curve is long and steep. But now I use it all the time.
There are drawbacks. For some reason, the manufacturer makes the channel so narrow it is very difficult to replace the rubber, even a Sorbo rubber. I use my conventional squeegee when not doing pole work, so I don’t have to replace it. It seems to wear the rubber out at an astonishing rate. When you extend your pole, the Wagtail is far less effective. You also can’t use an angle adapter to tuck thick frames; at least, I can’t.
All in all, it is like every other piece of equipment. It can be extremely useful under the right circumstances. If you do a lot of route work, it can knock off a good deal of time. If you get one, force yourself to practice with it until you become skilled in its use. We work in a cutthroat, dog-eat-dog business. Give yourself every advantage.