Firewire via expresscard vs USB
I'm planning to start doing a little light recording - just to help me get some ideas down for some solo work I'm dreaming of. I've got a fairly low budget right now, but don't need anything too extensive. I have a couple of mics (SM 58s) that should prove adequate, a lenovo laptop (6gb ram, dual core i5) that will be serving as my primary work station. I'm thinking of using Reaper, and am currently playing with/learning the program.
I am in need of an audio interface. I've been considering a few ( focusrite scarlett 2i2, focusrite 8i6, Presonus Audiobox, Roland QuadCapture, NI Komplete Audio 6 are some I've been considering) - all USB based interfaces. However, I've heard a lot of people suggesting Firewire instead. My laptop does not have a firewire port. but it does have an expresscard slot.
So, would I be better off going with a USB interface, or buying a separate firewire card and getting a firewire interface instead ( firestudio mobile? Sapphire Pro 14?)? I'm looking to keep things under 300 total (even less if possible) - at this budget range, does it make sense to look into firewire at all, or will I not notice a difference?
I know there's not a clear cut answer to anything, and I'll more than likely be happy with what I end up with - I just want to make sure I'm not missing something that I'll kick myself for later.