how does it compare to airport express?

I use an airport express in my 'main' room feeding an MF A324dac via digital optical output and another in my kitchen/diner using it's analogue output

Sounds terific with the dac

i tend to stream listen again radio 3 and hijack with airfoil but i occassionally use it to play stuff from my music library(own ripped cds for pod use in car)and it's close to the cd originals when compared, side by side as it were, into the coax input of the dac

the analogue out is ok for the other room

airports can be had for £60 or so and airfoil is $25

is the sb any better really?