For more than just the offseason
I've been using Zwift since 2015. Prior to that, indoor workouts were DVDs and dumb trainers that you manually changed the resistance on, and they were a drag. The short version of this review is that Zwift is a robust community where you can find everything from structured workouts and racing, to short and long (100 mile) group rides where folks motivate each other to do their best. The software works with a vast array of devices and makes it easy to get your miles in without having to gear up and head outdoors--or to prepare for your rides outdoors.