I make no claim for golden ears, just pitch sensitivity, a curse not a blessing. Measurement always trumps a hunch, though it doesn't always mean I'll ignore the hunch.
I've owned several Maxon motors from across their range, A-Max, Re-Max and EC and using different types of top bushing arrangement. I've used them with various controllers of different type, including tacho feedback, pwm versions right down to a simple current sense feedback- in this case the one under discussion here. I also used to run and SME deck with a DC motor. I've even used ones that claim to use feedback but have no active feedback loop in their design. So yes, I've used quite a few and I've measured them all. Though you are indeed correct I'm currently the owner of none of these, well spotted.
A strobe will show you if you are above or below a fixed speed, it's not much use for giving an accurate reading as they just aren't temporally sensitive, good for a 10,000 foot view though. A Laser RPM counter is little better than a strobe, it tells you what happens when the mark passes but not anything for a sample smaller than that. I don't know which phone app you use, but none of the ones I've seen are any more accurate than a paper strobe disc.
The problem with all of those measures is that they only really tell you the average speed. They are limited in temporal resolution and offer no real insight other than playing averagely fast or slow.
Maybe stop in at the 'turntable speed stability' thread in the diy section for greater insight if you have a genuine interest in achieving results that stand up to scrutiny rather than just consisting of opinion or regurgitated marketing hyperbole.
