replied in veterinary but basically, yes I feed it and "poor doer" TB does really well on it. So well only on one feed a day and it's fed with chaff, speedibeet and Pink Powder.
TGM advised me about it as it's cereal free so it might be worth PMing her.
I used it briefly when I could not get the Dodson and Horrell Staypower cubes and found B was a bit flat on them. The spillers cubes have digestable energy of 11MJ/Kg wheras the D&H are 12.5, the starch content in the D&H at 10% v 12% for the spillers. It depends what you want really - I need a reasonable DE with low starch (gets V tense on higher starch feeds) so although only a very small variance it made a big difference.
Find my horses do very well on it. 16.3 ISH, eventing, only gets three quarters of a scoop a day, but he lives out and has ad lib haylage. 15.3 WB x TB, will be eventing gets 1/2 a scoop a day.