I have the Phonic Helix Firewire 18 mixer, which is more or less the same as the Alesis you're looking at.
In some ways wish I had the Presonus/Behringer setup pandamonk suggested. I use the mixer (so far) only as a recording interface and while it works pretty well, it's much bigger than the Presonus to move around and the knobs and faders are useless duing mixing -- the firewire cable transmits audio but no other data.
I'm a novice at this, but so far as I can tell the preamps on the board are good but not great.
The one nice thing, though, is that I have 16 channels of audio input available so I can indulge myself (as a drummer) when recording and close mic my toms and aux snare while still having room to record the rest of the band. Can also submix the drums down to fewer tracks if I'm running too much for the laptop to handle at once.
I'm thinking abotu either the Behringer or a MIDI controller with faders so I can have something a little better for mixing. Really wish the board I have could transmit fader/knob positions as MIDI data, as well. Oh well.