I find them a bit too big for portable use and their comfort is meh. The best thing they have going for them considering their price is their looks and build. I think the Momentum On-ear is the better choice out of the two, especially for portable use. Of the two, it's the one I would go for not only because it's much cheaper, but because it's smaller form factor and is much more comfortable while sounding comparable if a bit different in terms of sound quality.
They do have some excellent sound quality except for the loose bass (when unamped) and narrowish soundstage but that's all. Narrow soundstage are found in typical closed headphones so it's not a deal breaker unless you are used to a more open sound.