Looking at some brushless servo - thoughts? Longer runtime?

[Gee]

Low on servos these days so I was looking at new ones to get. I stopped at this deal on tower.
http://www3.towerhobbies.com/cgi-bin...1&I=SE3226&P=K

It has two brushless servo and a rx. I could use all three items. The thought was that the brushless servos should use less then digiatal right?

Bashing with a brushless setup I never really paid much attention to the little things that are also hooked up to the lipos. But with the nitros I run started to take notice a little more. A 6v hump pack doesn't last that long. I get a fairly significant amount out time more out of a DX3R on the truggy below then I do from the 4PK on the XL.

The two setups
STRR
DX3R - SR3100
HiTec 5998TG steering
" " 5645mg throttle
.28


Sav XL
4PK - RS604F
HiTec 5955TG steering
Trx 2070 throttle
.32

There is a some weight different in the two and the Savage running 40's is going to take a lot more then the other. Well everything added together is the factor but will the brushless servo make a difference that will be noticed? Does the Futaba 4pk use a lot more power then the Spektrum dx3r? I've been meaning to swap the radio setup to see if what the differce it.