Many owners will debate what are the best switches for a car wash but in my opinion rotary switches are the best even though they are considered old school. Rotary switches are inexpensive and very reliable while push buttons are expensive and more prone to moisture issues. Keep it simple and easy for customers to use at your car wash while having reliability. While not as trendy as the push buttons, rotary switches work and rarely fail. With push buttons there will be trouble with water issues and in the winter with buttons freezing.