I have tried Sufferfest vids but I don't own a powermeter, so they're kind of wishy-washy if you're using an actual training plan and trying to get results. but if you're just looking for some motivation to get stronger/fitter, they're pretty fun. Especially if you enjoy watching races. There's a handful of folks on my team that play around with Zwift and say that it's pretty fun, too. Another thing to consider is many cycling development coaches will offer group training programs on something like a Computrainer. I've done a bunch of group Computrainer sessions, and those can be pretty fun and motivating. Quite a bit different than goofy spin classes since you're using structured training (training with power) rather than "PEDAL REALLY HARD AND TURN IT UP TO ELEVEN"-with-crappy-techno-music type training on an uncomfortable spin bike.