The performance of the brushless is generally less than brushed but they are getting better all the time.

There are some pretty good brushless servo's out there. I personally use Futaba BLS351(.13/60deg, 15.6kg) on the steering and BLS451(.10/60deg, 10.6kg) for the throttle on my MP9 Buggy.

MKS produce a good brushless servo BLS950 (6 volt, speed .12/60deg, 12kg), the servo is marketed as Turnigy also with the same part number.

Sanwa have brushless also but IMO not up to the required performance as yet.

I used to use KO Brushed but they cost heaps and only last a season before the brushes wear out. I found Futabe brushed to last a long time. Savox are very good value for money and have some very good performance figures.

I'm sure there will be other opinions pop up here as there is so much choice out there.