I’ve been very pleased with AT. I came off an 8 week block of DIY traditional base exclusively outdoors (~700 TSS/wk + ancillary training). Completed part of SSBHV2 and just finished Sustained Power Build 1. Naturally, I had to do some manual input to get my PLs to where they should be since AT was missing a lot of data: I felt I had strong sweetspot abilities (and obviously tempo and endurance). So, I just used the alternate tab to schedule a Breakthrough SS workout that looked achievable for me, nailed it, and let AT take the wheel from there. On the other hand, at one point I had a threshold workout scheduled on the very high end of Productive that I didn’t think I’d be able to complete, so I used an easier alternate that was still Productive and was able to do it–I felt like I got roughly the same benefit. I like having confidence that I’ll be able to complete my workouts. For those saying it seems too easy, I’d say that completing 100% of your workouts at 80% of the difficulty is more productive than completing 80% of your workouts at 100% difficulty. The best training plan is the one you can nail. And, you can always do some manual manipulation of the PLs as I did.
I find PLs to be really useful in judging the difficulty of a workout. Before the PLs, picking or replacing a workout could be a little like Russian roulette. Are they perfect? No. But it’s definitely an improvement.
For my money, any adaptive program is an improvement over a static program. Providing consistent feedback in the survey is critical–it’s about how you judge the workout and what each word means (Chad’s guide is useful but may not be the best for everyone). My major gripe is that I’d like to be able to pick and choose the adaptations that occur.
(nb that I am an exercise physiologist and track & field coach so I feel pretty good about my manual input)