Let me raise an issue which is tangential to what you asked, but really relevant.....
You might actually be happier with a stand alone recording device rather than recording directly to your computer using a computer interface.
I started out with a Presonus Firebox that I hooked up to a Mac laptop running GarageBand. I found this cumbersome and annoying in a variety of ways:
- My computer was loud (the fan would kick in - fan noise was getting to be a BIG deal in our recording attempts).
- I'd have to shut down other software before recording to guard against gaps in my recordings (here is an example of what can happen - note how the recording sort of skips at 20 seconds:
http://www.youtube.com/watch?v=xe7WxFURuQU ).
- Fiddling with menus and such in software to start things up and control the recording process was awkward.
- Also, unless you have a computer dedicated to recording you have to hook things up to your computer each time you sit down to record.
When I decided that we needed more than 2 microphone inputs and needed to upgrade I decided to go with a stand alone device and take the laptop out of the recording process. There are a variety of options. I chose the Zoom R24, mostly because it supplies phantom power to a large number of microphones at once (6 microphones), but you may not need anything this fancy. The Zoom is great. You can create a new project by pressing just a few buttons, and then you can start and stop your recording, review what you recorded, etc with simple clicks of buttons. The Zoom records on a standard SD card (and will accept up to a 32 GB card), and transfer of your files to a computer for processing is a snap (either use a USB cable or pop the card into a card reader - on my Mac laptop there is actually an SD card slot built in).
This being said, there are plenty of people who use computer interfaces and record directly to computers. And some deal with the fan noise issue by putting the computer in an adjacent room and using long cables - they start up the recording and then go into the recording space in the adjacent room and record (perhaps with a door closed between them and their computer). I found these issues to be big hassles that kept me from recording as much as I otherwise would have, but not everyone is as bothered by these issues as much as I am. You may or may not be bothered by these things, but these are definitely things to think about before committing to recording hardware of a particular sort.