Heya,
The XB series are absolutely hilarious looking. I think for at home use, who cares, go for it if you want better bass. The XB's will have more bass, quite a bit more, than the HD448's. The HD448's for some reason are advertized as `bass enhanced' headphones, but really, they're not all that bassy. The HD4xx series really sound great for things like acoustic, jazz, rock, indie, folk, etc. When I ran some electronic through them, I wanted something bassier. Plus, the HD4xx series headbands feel cheap and flimsy. I ended up returning them. The cord is also tiny and long. I just didn't like anything about the HD4xx series except they do actually sound good, but everything else about them is just cheap or junk feeling and that's just not cool for a $50~80 headphone depending on where you buy it. And then back to the Sony's. They're great, but goofy looking. I can't take having goofy looking headphones.
Why are you set on just these two headphones? Any particular reason? The only available options to you?
Very best,