I haven't read many of other comments on this topic but here is some info:
Solo:
The music quality is bad to say it mild, they break easy and they dosn't come up for the most fancy of the solos depending on black or white the ONLY TWO COLOURS possible to get from bestbuy, i have tried the solos and the HD but for me i ended up whit the studios, the solos are great for students it give you the needed music quality if you are not an perfectionist, these are the ones whit a little deeper bass(almost only diffrence from Solo HD) and thats why the mids and hights aint so good as the solos :3
Solo HD:
the HD's are like a mini version of the studios but the quality is ofc more grumsy but in solo vs solo HD the HD ones win whit their quality whit hights and mids, these dosent have the hard bass as the solos that makes the HD have more Lightly sound quality than the grumsy that the bass amkes in the solos, for me the puffs at solos HD is better than the solos but that can just be me
the fingerprints is nothing to care about if you have the white ones only if you have the black ones.
Solo = hard Bass + ok Quality built + middle great sound quality.
HD's = good Quality built + the looks is awesome + sound quality is 3x better than the solos
Conclution in my opinion is NEVER BUY THE NORMAL SOLO'S many peopke have problem whit them whit their headband breaking ect, so for me the HD's are the winner of the battle
OFC it says itself that the Solo HD are better than Solo, just read their names
<3 hope it helped you :3