I want to take them apart and review the components used. However, doing so will void the warranty and make it really hard to resell.

I tested 3 different ESC with the same motor on my Minipro dyno. One was an entry level Hobbywing, next was a Hobbywing Pro and finally a off brand ESC. They all produced the same acceleration curve. As was mentioned, acceleration doesn't really test anything on a modern ESC that can be compared. Braking is probably one thing you could test.

I think when someone say their new high priced ESC performs better, it's because they just spent a bunch of money and they want to believe it made a difference.

The differences between ESCs are in programming options and as an individual knowing what settings to change.

People are probably asking you to test different ESCs in hopes you'll find something that will give them an advantage. If such an advantage existed, every racer would use that ESC unless they were forced otherwise by sponsorship.

Yea...
I'm not expecting to find a big difference in ESC's, like there are in motors. I'm guessing my testing will only last for a few tests every other year. I would like to test the brakes, but I will need a flywheel, which is something I'm working on. The biggest reason for the tests is show if there is a difference at all. I see way too many people claiming one brand is faster than the other.

. Trophies

At the end it is all about the whole package.
The best car is nice to have but it is still te driver who needs to find the for him best working setup. And that counts for all parts like tires, battery, ESC, motor and most important the driving skills of the driver.
And then you have fanboys.... The reason why "what is the best" questions will not give the perfect answer. That is why I love where the ETS has become today with one ESC/motor combo, an RPM limiter and handout tires determined by the organiser to make it as best as equal possible.

friend attended an other country esc and motor controlled (hand-out) race, a foreign x-ray sponsored driver complained his car was being out placed in the main srtaight when they were coming out from the main straight and seems that was not possible by skills/car handling. everyone was surprised at site.
a moment later after the complaint/callout, the local sponsored (hand-out brand) driver ran with a "slower" motor as others,......

Trophies only show that equipment as being capable of winning a race. For example, if one brand was better than all other brands, then that brand would lead, and win, every race with no other brand ahead or between them. However, this is not the case. Also, when you compare sponsored racers to regular racers, then that isn't a good comparison. Sponsored racers get the top motors while the average sportsman gets the basic over-the=counter version of that motor.

this is not the case so much these days depending on manufacturers.

With gas racing it is pretty normal the factory drivers get the faster engines you can not buy in the shops, sometimes they even get the better pistons.

I can imagine the teamdrivers do get the better motors with maybe precise handwound stators, better strength/balanced rotors and ESC's with better spec FET's

This is mainly only the case with these companies that offer their tier structure when it comes to motors. Bronze, silver, gold type platforms mean you will sell poop to customers and charge a higher premium for motors that should be your standard. I’ve tested quite a few and been on teams when the cherry picking for team drivers were common practice. Take a companies lowest motor offered compared to their bells and whistles motor. 98% of the time the only difference is the rotor strength. Sensor phases arent better between the two.

This is true. Most manufacturers, with different level motors, will take the motors with the best numbers and set them aside for the better drivers and/or their buddies. To make matters worse, some distributers do it also. For example, Nor Cal Hobbies will go through the Team Powers motors and pull out the ones with the best numbers.

Now that there are no more limits on the IR, I'm afraid we will see a lot more differences in handpicked motors vs their low line. So, not only will the base model have weaker rotors, but they will also have a higher IR.

I suppose this thread is as good as any to ask this question, but what exactly is happening when an ESC is applying "brakes"?

It sounds like either the ESC is our of adjustment, or the transmitter is out of adjustment.

I believe his question is what happens inside the ESC when you apply the brakes.

IIRC in the brushed days, the two motor poles were shorted somehow and that created a braking force. Not sure about brushless systems. Never really cared for the details, tbh.

Back in the day with brushed motors, it was called regenerative braking, as they used the motor as a generator, and instead of using a resistor to short across, they directed the energy back into the battery. Brushless motors I assume would do the same, but they add the ability to change the pwm frequency of the braking for smoother, or more aggressive braking.