I grew up in Canada and we were taught that the BNA won, but recently I've learned that the issue is much more contentious than a clear winner/loser outcome. So who really won, and what evidence is there supporting their victory?
How do you define 'win'?
From the US's perspective, they achieved the goals they set out to accomplish (end of Impressment, end of British support for hostile Native tribes, reversal of harmful trade policies resulting from GB's war with France, etc), and lost no territory. In addition, after the initial opening moves, the US had great success repelling British military operations in the Southern states and the Gulf of Mexico.
From the British perspective, the US declared war, was invaded in return, had their capitol burned down, and was otherwise fairly soundly trounced militarily (though obviously any reclamation of territory was untenable) through the first half of the war, with the second half ending in more of a stalemate (no ground gained or lost).
I think the most accurate depiction would be to say the war ended in a stalemate, with the only real result being a return to status quo ante bellum.
I recently wrote an essay on this and determined through research that the biggest loser, was the Native Americans. They were used by the British, defeated, and any hopes of a free Indian Nation-state were trounced.
All in all though, the war never needed to be started and better diplomacy would have prevented it.