For the several years, I have been using BK servos exclusively. I actually purchased my first full set of DS-7001 cyclic servos and DS-7005 tail servo, only a couple of days after their release in 2013. 

I have been very happy with their performance and reliability, and I am certainly not switching brands for any other reason than to try something new. 

I have been using the Xpert KD1 servos now, for about a month, and I`m kind of still getting used to them. But I am really liking them so far. One of the coolest things about them, is how they start up. When the electronics are initialized, the servos actually chime. Kind of how an ESC chimes through the motor when you plug it in.  Then...instead of quickly "jumping" to center, they slowly move to center. 

They also have overload protection, which shuts the power off to them in the event of power overload. Probably one of the most thought out part of these servos, is the ability to be unplugged at the servo body. No more unwiring the whole helicopter to change servo gears, or to do maintenance checks. 

They came to me very nicely packaged, with two different lengths of servo plugs and a few stickers. The cases they came in even have little slots that hold the servo in place. 

They are very well made, and look great too. But they fly even better. These things are fast, very smooth, and have way more toque than I`ll ever need out of a servo. I have 30-40 flights on them so far, and I`m really enjoying flying them.  As I get more comfortable with them, I`ll have more input to share. So stay tuned in for that. 

As always, Happy and safe flying. :)