Who won the War of 1812?

It was a draw. Pretty much a 0-0 draw at that.

The only point at issue really was the British blockade of Napoleonic Europe and the consequent interference with US shipping.

At sea, the more powerful American frigates had some considerable successes in single-ship engagements with British ones - with the notable exception of the Chesapeake and the Shannon, but obviously couldn't stand up against the British fleet. Off the top of my head I don't think the Americans had any line-of-battle ships at all.

On land (and lake) it was pretty much a stalemate. The US successfully defended New Orleans and Lake Erie ("We have seen the enemy and they are ours") and failed to defend Washington, but the whole thing was just a side-issue to the British who had more important things to worry about.

Once Napoleon fell the whole thing was entirely pointless and everybody agreed to just give up. It's a bit of a pity though that the news didn't reach New Orleans a few days earlier.

If Britain had not been in the Napoleonic War it's doubtful the US would have declared war.

Similar with the purchase of Louisianna and invasion of Florida, they were Napoleonic wars sparked.

I tend to think the winner of the war was neither Britain nor the US it was Canada. Prior to the war the US thought Candians akin to themselves eager to shed Britiash shackles and just waiting a catalyst. They believed the Canadians would rally to the 'liberating' US army as it crossed the border. The original name for the war in the US was the 2nd War of Independence.

What the war did was kill any American pretentions for a northern expansion and showed them they clearly weren't welcome by the locals, thus focussed Americas ambitions westwards. One could say Canada won the war and the Indians lost it.

As an anecdotal observation, it can be said that the loser of the War of 1812 was the Federalist "party."  Their virtually unanimous condemnations of Democratic Republican policy that resulted in "Mr. Madison's War" backfired on them.

The popular image of the war was of American victories on Lake Erie, Lake Champlain, at New Orleans, and the success of U.S. navy frigates at sea.  Failures in Canada were forgotten; the bombardment of Baltimore became a national anthem, and Washington was burned.

Still, it was how it was perceived, and how it ended up.  By 1817 the Federalists were destroyed as a political force (except in Massachusetts until the 1820s)  They backed the wrong horse. 

Britain stopped pressing US sailors before war was declared.

I think this was just a popularist piece of tabloid properganda used to sell it to the public at the time and had little to do with the real reasons.

The war wouldn't have even occurred then because the blockade of Europe wouldn't have been in effect, and then even if it did, France probably would have stepped in against the British again and it would have looked a lot like it did in actuality.