My experience (take it with a grain of salt) of the preamps from worst to best:
Behringer
Mackie VLZ
DMP3
I have not heard the Spirit M series or the Mackie dfx.
...The Spirit M series pres seem to get the nod over the Mackie VLZ pres slightly, and the Spirit EQ is much more musical than the Mackie, or so it has been reported by a few sources on this Board and in the reviews I have read.