Okay the first thing you should know is a bandsaw mill isn't a high production machine for doing 2x4s and other dimensional lumber. A bandsaw mill is good for finer cutting like cedar siding or lumber for furniture etc. If your looking at cutting 2x4s 2x10s etc you look at buying a mobile dimensional saw which is built in Oregon
http://mobilemfg.com/
Things to consider with a bandmill
What size of wood you want to cut ?
The throat size on the mill limits the size of wood you want to mill
Length of wood you want to cut ?
Wood Mizer mills are limited to the length of lumber usually its 20' is pushing it.
Bandsaw mills need
ABSOLUTELY clean wood no dirt in the bark etc.
The wood needs to have no wind twist if it does the blade binds and snaps.
If the wood your cutting has been skidded and it has dirt on the bark it kills bandsaw blades like crazy.
You will need a few spare blades I would say atleast a dozen you also need the sharpening set up along with the teeth setter. Before you start the day you spend a couple hours sharpening blades.
I have worked around a wood mizer for the last 10 years never got behind the controls but worked as a labourer. I haul wood from the guys with wood mizer mills.
As for brand of mill you really can't go wrong with Wood Mizer a LT40 would do good enough for basic milling.
Last thing to leave with you I hope you have a good strong back because milling wood is hard work. I know my back was screaming for mercy lifting some of those planks and timbers.