Ding, ding, ding!! Winner, winner, lobstah-flavored, chicken dinnah.
That question was what this new law was about. Open carry has been recognized for a long time, but, if you put your jacket on and your jacket was long enough to cover your sidearm, boom, you needed a concealed carry permit, special training, pass a background check, and get special permission for your local (or state) constabulary. For...the...act...of...putting...a...jacket...on. I do realize that concealed carry usually means IWB or some other deliberately method, but our law made no allowances for either method. Shortly, it won't matter.
We also still need permits if we want to be afforded the "special rights" granted by the Federal Government to permit holders. Maine, being a very scenic and beautiful state with several federal and state parks, having a permit allows us to carry within most of them. We also get reciprocity from other states.
Yes and no (see below). Maine had another law passed and signed that removed the discretionary recognition of out of state permits from the chief of the Maine State Police, and now simply reads that if your state recognizes Maine permits than we automatically recognize yours. By the way, there is currently 23 or 24 states with reciprocal agreements with Maine.
When the law takes effect, out of state carriers won't need a permit. Like the argument that says that there is no excuse for ignorance of the law; by extension, the law pertains to all who are within the jurisdiction of the state of Maine. One thing to keep in mind, if you carry "pursuant to" this law, you also have the responsibility to inform a LEO during an encounter with them (arrests, traffic violations, or detainments).