I can't speak for all of the different interfaces but I would advise stearing well clear of the M-Audio Quattro. There was a forum running a few years ago with so many people suffering from all sorts of probs with this unit. Its very incompatiable with certain makes of PC laptops. I wish 'd found the forum before I bought the unit. Before you buy an interface type 'problem with (Interface name)' or '(Interface name) driver errors' as research.

My advice when getting a laptop for audio use is to check how audio plays through it before you buy. I guess this might be difficult with a company like dell but I strongly advise it.

When I got mine a few years ago there was an issue where the standard headphone output gave out loads of digital nastiness when the laptop was plugged in to the mains. I could have used an eternal I/O to solve the problem but thats not always convenient. My research when I was trying to sort this out revealed that this problem is quite random, some makes of laptop have it, others don't. Some have completely different problems. I eventually used a mixer with a ground-lift do sort it but this isn't ideal.

Anyway, thats a couple of issues I'd recommend looking out for based on my experiences. I'm a dedicated hardware fan nowadays. Be careful.