For me, spray basting was definitely a learning process. I have tried 505, Sullivan's, June Tailor, and even Aqua-Net! I eventually learned that the spray was not my problem, it was my technique and the temperature. We live in the Denver area, so I learned that in the winter, when our house is cold, the spray basting just doesn't stick. I have to do it in a warm room and on a hard surface. I have found that the dining room table and the wall in the dining room work the best.
I think 505 is the best, mostly because it has little to no odor. The Sullivan's works well but it has lots of overspray for me and it smells awful! It took me longer to clean the overspray then it did to baste the quilt! The June Tailor works if you are going to quilt in a day or two, but after that it started to lose it's tackiness. And the Aqua-Net also worked fine on small pieces that were quilted right away.
Don't give up! It took me a good 6 months to figure it out and now I see what all the fuss is about! Just keep trying. Start with small baby quilts, wall hangings, place mats, etc. until you get the hang of it. You'll get it!