I own both the 175 and the 185's and I see reviews where the 175's get bad reviews pretty much everywhere compared to the 185's... I honestly don't know why. The main difference I can tell from the 185's and the 175's is that the 185's are softer on your ears due to the pad design and being an open phone. I personally prefer to use the 175's over the 185's. The 185's are clean sounding, but they lack the bass and mids in my opinion. (The 175's are more than likely just upping these frequencies so they are more dominate) I also feel like I have to turn the 185's up louder than my 175's to get the quality/sound I want in the mids on the 185's. I just find the 185's kind of boring, even when using the bass boost option paired with my 175 base I just still prefer the 175's. I have both headphones hooked to my computer via optical so I can play FLAC music and the like and in an A/B comparison with people not knowing which is "supposed" to be better, everyone I know prefers the 175's.
Music tested was dance,techno, country, acoustic, and classical.
The best way I can describe the "feeling" I get from the 175's is it makes me want to dance, where the 185's are just nice to listen to. It's a totally different experience.
I use my 185's mainly for working out in my home gym and for moving watching and for this purpose they are great. They allow you to get in the zone easier as they block out sounds and with the lower frequencies being a little louder and punchy I feel more immersed. They enable me to really get pumped when I am using the elliptical. I also find them better for movie watching. The 185's are a nice sounding headphone, but they just seem to be missing the mid/low end punch that I have grown to love on the 175's. I used to own ATH 50's and the 175's give me more of that style sound signature.
I have to say, the first time I played the Binarual Test I nearly crapped my pants with the 175's! I literally grabbed for my sidearm. I never knew headphones could make such realistic noises. I have played the same tones on my 185's and they sound great, just not as real and scary! haha! Especially if you have never done the test before and have no idea what to expect. I had the wife sit down at my desk and played the test tone. She immediately stood up and started looking around.
http://www.audiocheck.net/soundtests_headphones.php
Both are good phones. If I was to do it again, I would honestly buy two 175's. Everyone's taste is different. The 185's may be better on paper, but for me they just lacked too much of the lower end punch/bass that I enjoy.
The 175's aren't without drawbacks.
The 175's headphone pads are harder on your ears, if you use the bass button on the stand it pretty much makes everything muddy and worthless for music. I can't stand the bass feature for music. However, for movies they are fantastic. I always enable the bass feature when watching movies.
The mids/bass tones may be more blown out or exaggerated... So if you don't like bass these are not for you.
The 175's to me are like going with a wireless ATH-50. The 185's are like going with a typical Sennheiser headphone. That's the easiest way to explain them to someone.
Hopefully that helps others out there.