Time series forecasting with multiple seasonal cycles is the subject of my scientific interests. I use methods based on patterns of seasonal cycles. The patterns used as input and output variables simplify the forecasting problem filtering out the trend and seasonal variations of periods longer that the basic one. The nonstationarity in mean and variance is also eliminated. Using patterns and different models like similarity-based models, neural networks and linear regression I got better results than using standard ARIMA and exponential smoothing. My articles on this topic can be found on my website: http://gdudek.el.pcz.pl/publications.
I am curious what are your experience in forecasting time series with multiple seasonal cycles. What methods do you recommend and why?