They are better because they are way more efficient in terms of speed and power saved. Also they last a lot longer because there are no armatures or brushes to wear out. I would probably bet that the bearings last longer too because there is no carbon dust from the brushes getting all over everything.

They require calibration to your transmitter's trigger swing. You can also adjust timing and on some, wether to have reverse or not and more. They are expensive because they are new to RC. Brushless systems aren't new, but the small size of the controllers is.

Most of the brushless ESC's are air related...made for helis or planes. These controllers will not calibrate to a pistol grip transmitter because of where the trigger is in neutral...it's in the middle of the trigger swing. You can use these controllers if your transmitter has a mechanical adjustment to take the brake swing out of it. ...or, rubber band the trigger forward for neutral.

...hope that answers some of your questions.