No question about it being solid…You can slam the power down and the bike is going absolutely nowhere! I haven’t noticed any issues with it being so solid though to be fair. I have only done 1 “long” ride of 2.5hrs on it so far and all was OK. I would be tempted by a rocker plate for it but not sure if any on the market could handle its weight…
This was one of my concerns too and the first time I rode the bike I did wonder If I had made a bad choice as my OG Tacx Neo was great in ERG mode but to be honest I have moved on and have no issues with ERG now. Sometimes it fluctuates a bit more than I would expect but its minor and has not affected my workouts to date. Sometimes it takes take a bit long to “get up” to target power which I could see being a problem for short high power efforts, but I would switch to resistance mode for these anyway and as above the ability to toggle ERG and Resistance in TR was one of the factors that influenced my decision.
On a side note I have had good success with Power Match in TR using my Assioma Duo pedals and the SB20 - in fact this is how I have been doing all my ERG workouts since around day 3 of owning it!