Yeah, dude, definitely keep the clean vox. Your growls are really, really impressive dude...a lot of sustain. Your cleans aren't bad at all; what do people expect, Bruce fucking Dickinson? Are you sure that the negative comments you received weren't from nu-metal fags that didn't like harsh vocals? I know that the most common thing that I hear from some dork who likes Korn is, "Wow, I really like the music, but I just can't get into the vocals. I don't like those growls, you can't understand what they are saying." I usually want to punch people in the face for being so simple-minded.
Anyway, are you singing from your throat or your diaphragm? Your clean voice has kind of a drone to it, but it's FAR from bad. Shit man, look at Dave Mustaine. Ever heard him sing live? HE SUCKS. He's my favorite guitarist, but he sucks as a frontman. People who don't like his vocals on his albums REALLY won't like him live. Live, he sounds like he's straining to take a shit because his voice is really high pitched. I think you should go for the thrash vox, though. That would be a perfect medium; James Hetfield meets Layne Stayley.
I'm far from a professional singer, but I have a pretty decent voice; it's good enough to be a frontman, although I'd rather play guitar. I just keep a good, clean, steady tone when I go clean...I do this by mainly singing from my diaphragm. You probably already know this, but push all the air out of your lungs with your voice, and it will come out cleaner and actually stronger, rather than singing from the throat. The throat tends to limit your range to low, droning tones because you aren't exercising your voice, only SOUNDS of your voice. Classic examples of this are frontmen like Scott Stapp of that garbage band Creed. He doesn't have a good voice. He has a very strong, low voice, which he uses to his advantage. By enunciating certain syllables and vocal patterns, it comes out really strong, but limited. Basically he's talking and humming at the same time.
On the other hand, you have people that do have really strong voices, like James Hetfield, but through improper singing techniques, they lose their voice after about 10 years of non-stop touring and bad vocal techniques. No warm-ups and singing all from your vocal chords blew his voice out. He had to take singing lessons, and now his voice is strong, but he's lost the roughness around the edges that made it so fucking awesome. When Dave Mustaine was asked to warm up his voice when recording an album, he hocked a loogie, spit it into the trashcan, and said, "Ok, I'm warmed up." I think that speaks for itself when you hear the vocals on Megadeth's newest live album.
Also, don't forget it's personal preference. I would classify your band as having a sort of Gothenburg-sound meets traditional metal, meets thrash metal. That song "Away" has a kind of "Hallowed Be Thy Name" from Iron Maiden tempo and feel to it. I will agree, however, that the clean vox sound ALOT like something from the hardcore punk band 88 Fingers Louie or Dillinger Four. Mainly because punk sings in a very flat, droning voice that's pretty fast tempo. Actually, the song "Fallen" has a sort of punk feel to it.
If I were you, just keep doing what you love. If it fits with the music, which it does, nothing's wrong. I can remember when harsh vocals were taboo, period. Back in the day, the harshest vox you got was from Metallica, Testament, and Slayer. Maybe Venom too, but you get the picture. It's all perception.