154* still causes an appreciable amount of isomerization (i.e. bitterness). 120* does not, so my prediction is that this beer will taste sweeter than the others.
As for "behaving like a short dry hop", I have no idea. But I'm very curious to know how the hop flavor/aroma turns out in this beer. I've never heard of nor tried hopping at that kind of temp, so anyone's guess is as good as mine. Although, my guess is that the hop character will be similar to a flameout addition, seeing as how fermentation will scrub out a lot of it, and oils/resins will stick to the yeast, as they always do...