Part of me knows that fast group rides / races are the best way to get faster. I use a set of 20 + year old Performance rollers with the turbo fans. Adding PM pedals and Sufferfest has changed my training routine; riding at rush hour is replaced with structured Sufferfest workouts. They complement the road rides nicely. I suppose I could do Zwift with my setup but there are parts of the equation that would be missing. The attraction of pushing beyond Sufferfest workouts is tempting though.