Were your comparisons based on 2 intervals at 150 and 200?
If so... how long were the intervals? You compared avg power for both I assume?
I apologize that fast first comparison was based just on "looking" at the SRM PowerControl and a Osynce Navi2Coach recording the ANT+ data from the Neo. Here now the mean values for the intervalls evaluating the fit files with GoldenCheetah. The NEO was controlled by the Tacx App in ergo mode via BT and an IPad:
Interval 1: ~10min; NEO: 150W 93rpm; SRM: 159W 93rpm
Interval 2: ~5min; NEO: 175W 93rpm; SRM: 182W 93rpm
Interval 3: ~5min; NEO: 175W 84rpm; SRM: 180W 85rpm
Interval 4: ~5min; NEO; 200W 84rpm; SRM: 204W 85rpm
Interval 5: ~5min; NEO: 200W 97rpm; SRM: 207W 97rpm
Interval 6: ~5min; NEO: 174W 94rpm; SRM: 183W 94rpm
Interval 7: ~5min; NEO; 175W 77rpm; SRM: 204W 85rpm
Interval 8: ~5min; NEO: 150W 83rpm; SRM: 157W 83rpm
Interval 9: ~5min; NEO: 150W 95rpm; SRM: 156W 85rpm
But bear in mind, this was just a simple fast an dirty test, nothing more! For example average power values were obtained just be marking regions on both fit file data in GoldenCheetah thus they can not match perfectly.