Your milage may vary, but I find that adaptive training does an amazing job at fine tuning VO2 max workouts for me.
I never feel I have much in the tank and I very rarely fail VO2max workouts.
If I didn’t have that confidence in the system I’d be more inclined to agree with you.
No relevant experience with TR’s adaptive training, but given that it’s designed to be used with erg, then that’s probably the way to go. Whether that’s optimal training or not, well, that’s a different discussion. 
I use erg mode for TR workouts, allows me to shut down the portion of brain that needs to focus on holding correct wattage, frees up that oxygen to be used by the legs instead of the brain.
I always feel like in Erg mode you are pulling a sled. It is fine (and helpful) when trying to stick to a certain wattage but when doing VO2 I just want to go and not feel like I am being held back. But that’s me.
I just wanted to pop in and clarify, TrainerRoad isn’t designed specifically for ERG. You can use it however you prefer: ERG, Resistance/Standard, outside rides, or any mix of those. TrainerRoad works across all of them, so you’re not locked into one or another. At the end of the day, the best way to train is whichever one keeps you consistent and motivated.
On Zwift I use Erg for endurance and recovery workouts.
For all else I use Erg with the TR app. I really like the speed in which the TR app controls the trainer.
Using a Wahoo Kickr v5
That’s a good point actually….. erg mode control via the TR app is better than on zwift in my experience.
My last comment was meant more about doing VO2 and anaerobic work at a fixed % of FTP. I recognize that TR works in all trainer modes as I used it accordingly over the years.
TR is significantly better.
In terms of trainer ERG control, I haven’t found any difference between apps when using my trainer for power. The app sends a new interval power to the trainer, and the trainer does the rest in regulating resistance vs rpm. The app is not involved. Using a PM for power is a different story. There, the app gets in the loop wrt to resistance vs rpm regulation and can make a big difference.
Other than that, some apps will send a new interval power a few seconds early or in several steps over a few seconds to make the transition a little less abrupt, but that’s only for a few seconds at the start of an interval.
Essentially all the time except in very short duration efforts (<20s).
ERG is too slow on my trainer to deal with the rapid changes. However, i do use it on 30:30s to great effect.
It’s very useful on efforts >1min.
Now that we have the new AI system, what do we think about ERG vs non-ERG for VO2 workouts? Do we think AI is picking the perfect intensity for us, and we should accept it and use ERG, or should we be in resistance mode and pushing as hard as we can?
Posted this in another thread but probably more relevant here - @eddie any idea if Trainerroad has plans to do something like this?
Never used Training Peaks Virtual but read recently that they have a neat ‘auto-disengage ERG mode’ feature to prevent the spiral of death when your cadence drops below a certain value. Once your cadence is back in a healthy range, the ERG mode gently re-engages, gradually bringing the resistance back up to the workout’s target power. This gives your heart rate and muscles a few seconds to adjust to the load again.
How do you set that up? Do you do a free ride on Zwift or does the workout run in parallel? If so, how do you start them simultaneously?
I just do a free ride in Zwift.
All you have to remember is to not link your trainer as “controllerable” on zwift so only the TR app controlls your trainer - both can read power at the same time.
Then run the TR app on another device (or the same device if like me you have a PC and both ant+ and bluetooth connections…).
Because zwift is separate to the workout you can duck in and out of events/routes/pacers etc all while the workout is going on via the TR app.
But maybe it /does/ change something - mayyyybe the VO2 workouts we’re being prescribed now have more suitable (higher) power peaks to hit, in the eyes of those who used to think ERG was a mistake and led to under-utilisation of the zone. 
Basically I’ve only ever done VO2 in ERG. Today I’m about to do my first ever outdoors TR workout. And it’s a VO2 one. I’m not sure if I should be aiming to hit the power TR prescribes, or if I should be fully burying myself in each effort.
I guess burying myself is the answer though - either TR vo2 is too easy, and I should push harder, or they’ve ramped it up and the efforts will feel like burying myself regardless.
Nothing that I know of at the moment.
Both can be true. All of the traditional VO2 workouts I’ve done in ERG with TR have brought me to that “fish out of water” state. Just like with any other zone, we can dial things in pretty quickly.
Not all VO2 workouts are designed to achieve this (at least not in the same way) and so I typically just follow the power targets.
If you’re getting traditional, high-level workouts like 4x5, 5x4, etc. and you prefer to just hit it hard from the gun and let your power taper off to get to that state as quickly as possible, feel free to go that route! 
n=1 erg is the reason I have a smart trainer. Personally, I’ve found TR VO2 max work fine at the power levels, and using erg mode. I know I’m in the minority, but I actually prefer zwift erg mode to TR - not sure I can quantify why, but really don’t get the stuck in sand feeling others seem to!
You will see people from TR saying to just use ERG mode, though. 
VO2 is really no different than another power zone in my opinion. So, to the original asker of that question, I’d say, yes, use ERG mode as we’re better than ever at picking the right workouts for each athlete. 
Hmmm. I didn’t use ERG (was outside), and went about 50W above prescribed for each interval, and my predicted FTP two weeks out got a 2W bump. Mixed messaging, TR! 