[C x 2]

 
I made 2 comparisons of the frequency responses from the HE-400, HD600 and HE-500. The HE-400i is not exactly the same as the HE-400, but it's similar. You'll see that the bass on the HiFiMan headphones has a better extension, but you'll also notice that the upper mids / lower treble of the HE-400 is very different from the other two. Female vocals and violins are likely to sound less forward / less natural on the HE-400. The HD600 is known for reproducing those frequencies in a very natural way. Until you have the money for the better models of HiFiMan, I think the HD600 is the better choice for you.

I see, thanks for the tip. 

 I was curious about the HiFiMan headphones, but they're definitely an upgrade for another day. 
 

Peel of two stickers and those are nothing but lies and slander

That's just from what I read and heard so far, I can't really give a proper judgement since I've never used a pair myself. 

 

[JoeDoe]

Based on your listienng preferences, I say you want a slightly mid centric can that still retains some detail in a smoother top end. In order of preference:

1. Hifiman HE500 ($400-450 USD used) or HE400i ($350-400)
2. Grado RS1i ($400-450)
3. Sennheiser HD600 ($250-300)

Look up the impressions and reviews of each of these. They're all extremely well received and excellent all rounders.

 

[C x 2]

Based on your listienng preferences, I say you want a slightly mid centric can that still retains some detail in a smoother top end. In order of preference:

1. Hifiman HE500 ($400-450 USD used) or HE400i ($350-400)
2. Grado RS1i ($400-450)
3. Sennheiser HD600 ($250-300)

Look up the impressions and reviews of each of these. They're all extremely well received and excellent all rounders.

Thanks for the suggestion. I've already looked up impressions and reviews for those, I'm going to give the HD 600s a try first though.