Hello,
I have SF-1s and really enjoy them. I think for their price, especially in the US, they're great speakers.
To me, they sound best if you cut them round about 80Hz and give the 2 first octaves to a fast sub, because they're not very precise in the 40 to 80Hz range (and of course can't go down to 20Hz).
The other slight issue would be that they get a bit harsh sounding when playing very loud, but honestly do very well at reasonable volumes. SF-1s are the speakers that made me like the Klipsch sound! []
And now most other brands sound kind of bland to my ears.