The Emu sounds great, has excellent converters and works well with Cubase.
But I won't lie to you, it can be difficult to install if you don't know how to tweak your pc or have the patience for it. There are some undocumented incompatibilities with certain mobos/video cards/onboard sata among others. Others have reported dissatisfaction with the drivers although my personal experience is to the contrary.
The Presonus is ok; I'm presuming it's the Firebox - I heard the Firepod has better interfacing options. I've read good reports about those 2. Also, try checking out the Echo Layla 3G
. Go over to www.recording.org for user comments on these interfaces.