I’ve also had a few American ones, most ofter from the Spoetzel Brewery in Shiner, TX and Widmer down in Oregon. I’d say they suffer from lack of Bavarian weizen yeast. Going from memory, the Widmer probably uses a neutral American Ale yeast, while the Spoetzel Brewery (I’m guessing) uses a lager yeast. I suppose this highlights the difficulties of using more than one yeast strain in your brewery (contamination could be a problem). The best commercial variety has come from Life Oak in Austin, TX. It’s rather smooth, but still somewhat light on the banana and clove esters.

But as you say, hands down the best US wheat beer I’ve tasted has been my own weizen dopplebock. It was GOOD.