Going by initial goals, it was a successful defense of Canada by Britain. The US went in with the hope of caputuring Canada and wiping out the British-supported Indians in the North-west, and in the end got kicked out of Canada and then some. However, the Indian threat did get smashed.
Going by evolved goals, it gets debatable. Both sides certainly changed goals and intentions as the war evolved: the US just trying to stay togetherr, while expanding the campaigns even as far away from Canada as New Orleans certainly indicates more than 'just' protecting Canada, which had already been achieved by that point. Certainly there were voices in British circles about carving up parts of the US, if not all of it.
So the US failed in its initial goals (seize canada) and succeeded in its later ones (to reamain intact, independent, and not under undo British influence), while Britain certainly succeded in its initial objectived (protect Canada) but achieved little, if anything, else (no major concessions from the US, no enforcement of Britich will over future US policies, etc.).
I won't go into who really 'won' the war, but I will note that the conflict did have benefits for the US. The peace saw the British abandon forts on the Frontier in American territory and saw much less support for the Native Americans, who were soon smashed as a force in opposition to settlement. The conflict-turned-crisis also established a period of nationalism that helped unify the US as a nation, saw the Executive branch exercise its war-leading powers for the first time, and overall set the tone and traditions that would effect the growth of America from then on. People mention how 1812 saw the birth of a Canadian identity in opposition to the US, but the War of 1812 was also the birth of American identity and nationalism.