I have been there and done that (and answered this question on Talkbass more times than I care to count.. doesn't anyone use the search function anymore?)
I use the MOTU 828 with a Powerbook G4 as well as a desktop PC. I like it, and recommend it. I've got a friend who uses a Firepod + PC laptop. He likes it, and recommends it. As far as firewire interfaces go, it comes down to this:
- If you eventually might need to expand beyond 10 channels using existing gear or do an equal mix of digital and analog, get the MOTU 828. This is because the 828 has the capability of adding an extra 8 channels via ADAT. The Firepod will not do this.
- If ten channels is enough, get the Firepod. Its Windows drivers are more solid than MOTU's "we wrote it for Mac and eventually got around to making it work with Windows" stuff and it's got somewhat better mic preamps than the MOTU gear does. It also has eight preamps built in vs the 828's two, which will save money in the long run.
For me, the lack of expandability with the Firepod was a deal-breaker. I need to go beyond 10 if I'm doing a field multitrack recording of a band and the ability to hook two Firepods to a single machine was in beta the last time I checked. There are other ways around it, but because I bounce between OSes and hardware, firewire is really essential to me. An 828 and a Presonus Digimax is a rock solid 2U setup.
For what it's worth, I really like Presonus as a company and I think that the Firepod is a better product. But both pieces are great.