The K454 is great for country, Youtube and movies and I think you will prefer this one because it is much more portable than the Momentums. I’ve just tried some hip hop and house music and it is not bad at all.
I will review the Momentums in the next 1-2 weeks and I could give you a better recommendation then.

No not at all, just want a pair of headphones that are all around great for hip hop, country, house and alongside watching YouTube and movies on.

Yeah I know,
I was also very surprised as the carrying case is not included like the specs said. I’m not using an Otterbox Defender case on my iPhone but I tried the Otterbox case on Samsung Galaxy S4 and there was no problem at all.
I am not sure about the Sennheiser Momentums because I haven’t tried that one yet. AKG K545 is a decent headphone but if you are expecting an impressive bass response, this shouldn’t be your choice.

http://us.akg.com/tl_files/catalog//AKG/AKG/Spec%20sheet/In-Ear/K545/Specification%20Sheet%20%20K545%20(English).pdf

My question is about the headphone jack, will it be able to fit into an iPhone with an Otterbox Defender on it? I don’t want to buy an expensive pair of headphones only for it not be compatible with the case I’m using. Also which between these and the Sennheiser Momentums which ones do you prefer?

No Ramen,
This is a high-end headphone and I don’t think it is overpriced. Its old version is still listed for around $230 at the moment, that means its value drops by just $60 after 2 years.