I've seen some very good brake drum forges. My portable forge is a small farrier's pan forge, which is similar to a brake drum forge. Brick forges are also good, if built right. The advantage of brake drum forges is you can move them.

What kind of size are you thinking of for pieces? You can work large pieces in a BD forge, but it may be easier to set them in a brick forge.

Another consideration is cost. Find out how much materials will be for each.