I recorded my latest album with the Firepod - I didn't find any problem with headroom. To be fair, though, I don't really have much of any experience with higher-end mic pre's. I basically upgraded from a delta44 with a behringer MX-series mixer to the firepod, and the difference was AMAZING to my ears.
I did use an M-Audio DMP3 preamp with my delta44 for a little while, and I think the firepod sounds way better than that combo as well. I couldn't say if it was the pre-amps in the firepod sounding better than the DMP3, or the converters in the firepod sounding better than the delta44, or a combination, but it sounds better.
Like I said, my latest album was all recorded w/the firepod, and here are some songs from it to get a sense of how it sounds (clips will stream):
Something Better
Isn't She Wonderful
A bit more info on the clips: I use budget mic's - nothing high-end at all in my recording chain.
Vox: Studio Project C1
Acoustic Guit.: Stereo pair of MXL 603s's
Electric Guit.: Recorded direct (Line6 GuitarPort)
Bass: Recorded direct via DI from an SWR combo
Drums: Loops (Drums on Demand)
Considering the equipment used - I'm happy with the resutls.
Good luck with your purchase.