Has anyone had success due to spinning classes?

Yes!!!
Tuned up my racer. Bought a bike trainer (turns your bike into a stationary bike). Kurt Kinetic brand preferably. Could only ride for 5 minutes. Did not quit. Within two weeks I was up to 20 minutes a day. After a month riding 5 days a week I lost 5lbs. with a caloric intake of 2000 from 4000 (huge help). Instead of 235 I was 230. Then the motivation kicked in. Got rid of the cookies crackers soda...etc. Just cleaned out the kitchen of temptations replaced with fruit and veg smoothies.
Began to spin at home 20 mins twice a day, lost 8lbs. that month. Within 5 months I was at 200lbs riding 30 mins. intensely spinning much sweat. Got more involved in calorie counting thanks to MYFITNESS APP which was a HUGE help. Going to Subway? Have them pull the bread from top and bottom. No mayo or cheese or dressings. Now your winning. Its been 4 years of maintaining a weight of 170-175 spinning 5 days twice a day at 45-60 mins with tight legs butt calves arms shoulders and ab muscles. The most important spin for me is in the morning on an empty stomach. Get your 7-8 hours of sleep because after my night ride calories are still burning well into my sleep. Incorporate some weight lifting and you are going to have a body to be proud of. Got to remember one thing, it's a lifestyle.