Do you use a power meter? To get the most out of any of these programs, a power meter is strongly recommended.
I've used Trainerroad for a few years now and it is the best option for structured training plans with a specific goal and type of riding in mind - road races, time trials, sportifs/fondos, sprints, climbs, etc. Each plan also has low, medium, and high volume variants to suit your available training time. The program adjusts your power target during your workout to guide you through the intervals, making the workouts quite precise.
Sufferfest is going in that direction with its app and new 4DP stuff, but Trainerroad is the time-tested standard. 4DP has been the subject of quite a bit of vitriol from Andy Coggan (renowned cycling physiologist) over at Bikeradar for being derivative.
Zwift is more of a game than a training tool. It's possible to have structured training with Zwift, but that's not its focus.