I have not compared the two, but what you describe is kind of the definition of ERG. Essentially, the trainer changes the braking force according to flywheel speed to maintain a constant power. So, the faster you go, the lighter the braking resistance, and the slower you go, the higher the braking resistance. So, in your case, it sounds like you have a stronger aerobic engine to maintain speed with lighter pedal force. But, you do not have the leg strength to maintain a higher power target at lower cadence.

Makes perfect sense. Kinda like grinding in the 11 at 60 cadence vs spinning in the 28 on the road.

I dunno, I wouldn't say that sounds like a personal ability thing so much as how well the unit can control.

If you're doing something at a given cadence and nowhere near tossing in the towel, if you blip by 5rpm for 2 to 3 seconds and back up.......it shouldn't "lock" up making it feel like starting a track pursuit bike off the line.

Sounds to me something is wonky with the unit.

If power reading drops out but the power command is still in place.......it'll ratchet up the resistance. You using the unit's power reading or a crank/pedal/wheel power meter? You have a graph of where this happened?

I used ERG mode on my Hammer Trainer with Rouvy Software and love it. It feels so much more natural than when I bike a course on Rouvy....

Yep. As long as the power is constant for you when you drop to a lower cadence, it is probably OK. However, if the power spikes way up while also dropping to a slower speed, then it could be a unit control issue. Another test to see whether it is likely the unit or you is to experiment between your easiest and hardest gears. If you have the same experience with high and low wheel speed, then it is probably you. But, if one of the two is bad even at your preferred cadence, then it could be a unit issue.

I ride a first gen Snap and only do my rides in erg mode using the Wahoo app, but have not seen the same issue like you may have. I'll often do a training workout whereby I'll set my power to a level and ride 4' at a cadence of 100+, then 4' at 90, then 4' at 80, then 4'at 70', then 8' at 60, then again 4' at 70, 4 at 80, 4 at 90 and min at 100+ without changing any settings i.e. just changing my rpm by making my legs spin faster or slower and letting the trainer adjust itself.

I usually ride front chainring and middle of the rear cassette, and it works fine. Power accuracy (i.e. match vs my powertap or power2max) is a different story but in general it works as intended in erg mode for me.

maybe you mean that when the program changes from one setting to a harder setting ( ie 100 watts to say 300 watts for a sprint session)it grinds to a halt? That is a case of how the machine and the program work together to increase the change. In that case often it is best to spin up before the change to give yourself some room to get it to continue without grinding to a halt and also I think it is a software/firmware issue as to how fast it changes and then resettles. However I have no idea if this is implemented differently between the two trainers.