I applied some of the decals tonight and I couldn't be happier with the results.
Per the instructions, I cut out each decal and immersed it in clear water for about five seconds. It was transferred to a paper towel for another ten to twenty seconds while the decal loosened from the backing. Remembering back to my scale modeling days, I dabbed a little water on the plane where the decal was to go and slid the decal on - the extra water gives more positioning time. After it was in position it was gently daubed with dry paper towel to remove the excess water. In short, they went on just as easily as any other water transfer decal I've used in the past.
In summary, these decals were created on Testors clear decal paper with an Epson NX420 3-in-1 printer. They were sealed by three light coats of Testors bonder, with at least two hours' drying time in between. There was no smearing, smudging or running at all.