I use mine all the time and love it! Like you, I use it to filter grain from my mash tun. No Vorlauf ever. Just put the hose in the filter and open the valve. Then when the wort is coming up to boil temp, I just hose it off and drop it in the Boil Kettle for hop/spice additions.
My next purchase is their dry hop canister that will fit in corny kegs. I figure they will hold ~4 oz. of wet hops. Yum.