1. You need to be patient. Less than an hour and you're already jumping to that?
2. Very few people here have owned the PXC450 (I happen to be one of them though), so naturally there won't be many people here helping, unless you want them to pull things out of thin air and lead you to a bad purchase.
3. I preferred the sound of the PXC450 to the HD380, but the bass drop due to NC did make the levels of bass lower than HD380 from memory. Though the PXC450 responds wonderfully to EQ, so you can EQ to your heart's desire.
Then again, I would seriously recommend against paying more than $200 for these. At $200, they were okay, and the NC was acceptable (not nearly as good as Bose's) but unless you absolutely need NC, don't go for it. There are a number of $200 headphones I'd recommend before these. And if you need NC, I'd go for a used QC15 or UE6000. (It'd be helpful to state that I didn't like the HD380 either. I'd pick the $40 PRODJ100 over them)