Hey Guys,

This is one topic I have a lot of sometimes painful experience in. I've had over 30 USB and Firewire interfaces over the years. Some good, some really bad.
Here are a few tips I've picked up by studying the posts on pro audio forums and personal experience>

1. There is no such thing as "You get what you pay for". For Example, Echo Audio makes some of the most bullet proof and musical interfaces around, and you can get the audiofire 2 for $200. Built very well, no driver issues, solid as a rock and sounds great. Or you spend $699 and get loads of trouble with M-audio stuff, some of their interfaces will work for a while, but for the most part the driver and reliability are not good (Read the M-audio or gearsluts forums, tons of posts on units not working, failing, glitches, etc). The absolute pinnacle for USB 2 interfaces is RME, they have a model called the UC. These things are built like a tank, they never go down, the converters and Mic preamps sound great. The downside is the price.....$1,300.

I always thought that Firewire interfaces were better for digital audio, but there is a new video on the RME site that discusses the built in latency in firewire (6ms) compared to USB 2 (2-4ms). I was also concerned about throughput(the amount of information ofTracks/plugins available) but it turns out that with USB 2, it is about the same. USB 3 should up the ante considerably. The only downside is the new high speed USB interfaces are NOT bussed powered, meaning you will need to plug in your power supply.

Being in the Market for a new interface for the last month, I've spent hours reading reviews and posts by musicians. Here are a few standouts that I can see.

>Budget.....Echo Audiofire 2, 4 or 8. Good build quality, great sounding converters, great driver support, no reports of problems.Tascam>can be hit or miss for both driver support and reliability(I have had the Fireone for 2 years with some driver issues), mic preamps are not musical.
>Midline......MOTU Ultralite (USB2 AND Firewire connectivity!) Focusrite Sapphire. On the Mac side>Apogee One (USB) or Duet (Firewire) Great sounding converters, Great preamps, rock solid drivers, etc.
>Pro...........RME UC or 400/800. Lynx Aurora. Mac only>Apogee Ensemble. Mac & PC>Prizm sound Orpheus. Metric Halo ULN 2/2828
The above are considered the best interfaces you can buy with pricetags to match ($3-5000) Outstanding converters, Sweet pure Mic Preamps, Solid drivers and overall the best sound you are going to get. In fact, with any of these you would not need an external Mic Preamp.

The following are interfaces that have a pattern of reliability, driver, or build issues.

M-audio>I've had 7 of these interfaces in the last 10 years, with trouble in each model. They either work ok for a while and then die, or they don't work at all. Some have had good success with them, but be careful. Also, their tech support is less than stellar.
Presonus>Driver issues, build quality is ok.

Hope this helps you, also the above is the conclusions I came too, I'm sure many people will disagree and that's ok, we are all here to get the best bang for the buck, I'm always ready to learn something new or be proven wrong!

Ed