Speakers have a huge impact on the sound- some natural compression and quite a bit of high and low end tayloring. Direct Outs from the preamp don't have the benefits of those changes and so sound very different from the miced speaker. Line signals recorded with miced signals are also often out of phase- that needs to be fixed before it will sound good. I usually only capture DI tracks so I can re-amp them.
POD's and other amp and speaker sims are better in this regard. Its kind of the ultimate "What you hear is what you get." I personally don't like it as much as even a cheap amp with a 57 on the grill, but to each his own. No matter how you tweak it, its still a canned guitar sound.
So in my experience, no. I haven't worked on any serious metal projects where guitars are recorded direct. Preproduction, songwriting, farting around? Sure. CD for sale? No.
-Chris