[parasitius]

I've Googled every which way I know how, and I can't find anyone explaining if there is any sound difference and if the drivers are different. Also, is the quality of the build / materials substantially different? 
 
I haven't seen them in real life side-by-side but just due to the colors I could see myself easily preferring certain pairs of the budget line. But I definitely don't want to sacrifice sound for looks. None of the review threads are ever clear if they are reviewing the budget Momentums or the high-end (or as some sites label them 'luxury') momentums. How frustrating! I need to know which pair to jump on just incase the right black friday deal comes my way.
 
Thanks.
 
 
$229 vs $349

 

[deltasun]

Without getting into the nitty gritty, the on-ears just did not have the "full" sound and soundstage that the circumaural version had.  My local Best Buy had them both and so I was able to A/B them somewhat.

 

[kalbee]

There are sound differences, but mainly you need to be aware that they don't fit the same on the head at all.
 
The "budget" model, Momentum On-Ears, is fairly small and sits on your ears. Some people don't like the feeling, although personally I did not find them uncomfortable. The full sized Momentum has earpads that go over and around your ears.
 
As far as portability goes, the on-ears version is definitely lighter and smaller. But, it also does not isolate as well (YMMV) so if you plan on using them during commutes and such, keep this in mind.

 

[Saren]

  There are sound differences, but mainly you need to be aware that they don't fit the same on the head at all.
 
The "budget" model, Momentum On-Ears, is fairly small and sits on your ears. Some people don't like the feeling, although personally I did not find them uncomfortable. The full sized Momentum has earpads that go over and around your ears.
 
As far as portability goes, the on-ears version is definitely lighter and smaller. But, it also does not isolate as well (YMMV) so if you plan on using them during commutes and such, keep this in mind.

 
Also be aware that the "over ear" momentums earpads are actually very small themselves for something that is meant to be full sized. Some people have found them to sit partially on their ears which can be annoying itself.

 

[parasitius]

Thanks so much guys! 
 
I have amperiors right now. I hate that they aren't comfortable for long sessions at Starbucks, though I generally love the sound. I also hate the remote which has no tactile feel to differentiate the 3 buttons.
 
 didn't even realize one version of the Momentums is circumaural. To get that added comfort PLUS better isolation than on-ear, and still be fairly portable (am I wrong?)... sounds like a winner for my purposes )
 
I have to say Sennheiser did a poor job with the marketing for the majority of the country that can't find stores that sell such things to compare. They should have made the name slightly different.