I use Buck Spray all the time. I was their tester and I tested it against reg starch, sizing Best Press and the homemade starch with vodka.
I really like Bucko Spray. It does take out the hard lines that you find in a fabric fold, I tested reg cotton and flannel. I also did a test with he blue pen, the one that you are not suppose to iron it. Well I did and Bucko took out 90% of the blue pen. Reg starch did not touch it and Best Press took out 60%.
I took 4 bottles to my quilting retreat and had the 40 ladies try it out. They loves it. We also had Best Press .starch and sizing there.
I did Not get paid to do this. I gave a honest review. All said and done..Everything is up to the person how uses different products and it is always personal choice. Just like buying a sewing machine or car. You gotta test drive them.