The MBox is a very nice unit with two high quality Focusrite microphone preamps for capturing live sound. It also supports 24-bit I/O through its S/PDIF connections. Keep in mind that it only has two analog inputs and two analog outputs. The software can let you work in a 32 track environment on your PC, but the MBox does not actually have 32 ins and 32 outs. It also does not support sample rates higher than 48 kHz. This may be a limitation of using the USB 1.1 bus, which, for digital audio, has some limited bandwidth and possible resource management (i.e., IRQ) conflicts.
I opted to get an M-Audio Firewire 410 audio interface. Since my IBM ThinkPad laptop has two PCMCIA CardBus slots, I purchased a FireWire CardBus adapter and I use that to connect to my FireWire 410 for recording and playback. FireWire has significantly higher bandwidth for handling digital audio, so the M-Audio Firewire 410 offers four analog inputs (two with M-Audio's high quality mic preamps) and 10 analog outputs along with digital Toslink optical I/O connections and RCA S/PDIF digital I/O. It can handle higher resolution audio at 24-bit resolution and sample rates up to 96 kHz without straining the FireWire bus. With 10 analog outputs, the Firewire 410 can also be used for reproducing 5.1 or 6.1 surround sound with the proper software encoder.
Unfortunately, my IBM-brand FireWire CardBus adapter doesn't support 6-pin FireWire connections (only 4-pin connections), so I have to use the wall wart power supply to power the FireWire 410. Some laptops come with built-in 6-pin FireWire ports for handling digital media sources, and the two extra pins in a six-pin configuration conduct power just like a USB 1.1 bus connector. I am extremely happy to report that the Firewire 410 is capable of reproducing sound very accurately with depth and weight. Playback of some CDs on my laptop's drive revealed details I never heard through my Naim hi-fi system. I'm sure some higher end PCI soundcards from RME and Lynx Studio Technolgies will sound better than the Firewire 410, but this little guy is an outstanding performer for the price. My next acquisition will be a pair of Dynaudio Acoustics BM6a biamplified monitors so I can do some very serious listening and monitoring with the Firewire 410. So far, I've used the Firewire 410 with Adobe Audition 1.0 (formerly Cool Edit Pro 2.1) and Delta Live 2.1 (a light version of Ableton's Live 2.1), and I have to say that the Firewire 410 works extremely well with both applications for multitrack recording and playback. I haven't had time to tinker with the light version of Reason that came with the Firewire 410, but I am looking forward to doing that as well.
I would suggest that you check out www.audioforums.com and other pro audio forums to get an idea of what other users think of the MBox in terms of Digidesign's technical support with driver updates and technical service. Of course, you'll always find someone who has had problems, because they didn't take the time to really optimize their laptop for optimal audio signal processing, or they didn't carefully follow the manufacturer's instructions for installing the software drivers. The best guide to optimizing Windows 2000 or XP for digital audio comes from Tascam. If you can't find it on the Web through a Google search, email me and I'll email you the PDF copy. By the way, if you have a laptop and you're not running Windows 2000 or XP (XP being better), then upgrade the OS first. If you have a Mac, there are some good Web resources for optimizing Mac OS X for pro audio applications.