As far as energy savings are concerned, An 8-inch thick log wall is the same insulation value as a 2x4 wall with 2-inch thick insulation; in other words a log wall lets more heat pass through than a standard-build wall today.
A brick wall is good to stop the wolf from getting to the little pig; but a 3-feet thick brick wall is equal in insulation value to a standard 3" batt of fiberglass.
Both log and brick are used for decorative, aesthetic value, not for energy savings. The brick wall will be less problem. A log home must be watched for movement and air leaks - aside for the need to surface-mount the wiring and heat lines.