I dont have any 1st hand experience with tekin...
but last week at the indoor track a guy had a sc10 with tekin brushless system.

He would run a few laps....go into the hobby shop, come out and run a few more.

This process repeted several times.

Each time out, it did seem he got a bit faster. In the hobby shop, he used a laptop to tune the ESC.

On the one hand, the tuning that can be achieved is impressive. On the other hand, it was the electronics that got better.....not the driver. And to me, racing should be more about the driver.
I dont have a problem with tuning shocks...tires...springs...camber and such. All these things are tuned in real racing. And they are also things all hobbiest can do if they choose. Not all hobbiest can afford a tekin bl system.

But then, im probly only nit picking cause im one of those who cant afford them....LOL.

And for me, the tuning of the inexpensive ezrun systems is enough. You can still tweak punch, drag, initial brake, total brake and reverse power. Even those few bits can greatly effect how your truck will perform on the track.

I dont really race, but even in bashing I have to change the settings between models or between which lipo I use. When I run a 3s, I lower the braking...up the punch control ect. When using 2s, braking force goes up and punch down. Makes a big difference!