The winner of a war is the side that achieves political and/or strategical objectives, the loser is the side that loses political and/or strategial power. There's no doubt about it that we can at the very least say that the US is a loser in this war, they come out of it in a worse position than they entered it.

Then the only two remaining options are an Iranian victory or an inconclusive outcome. And there's a genuine argument to be made that the simple fact that US is a loser makes Iran a winner. Not only do they cement themselves as a local power, but they also have sanctions lifted, get to humiliate Trump with the 300 billion and basically didn't have to concede anything. The argument for it being inconclusive is the simple fact that it's not over till it's over, and right now it's still not over.

Personally I'd be leaning more towards the latter as long as there's no clear end to the conflict, but unless a very large shift happens it's going to be an Iranian victory.