Ive been using it for quite a few years on my veteran (30 yrs) cob who cannot tolerate chemical worming. I worm count and blood test religiously and Ive found Verm X works well alongside regular field cleaning.
Yes, I can't recommend it highly enough. More and more horses are having bad reactions to strong chemical wormers not to mention worms becoming resistant.
I also worm count along with the usual poo picking etc and my boy is in fab condition all year round, he also loves the herbal wormer in his food so no probs there. As I understand it, the herbs used in Verm-X act like a natural detox/cleanser too so a very shiny coat, bright eyes and full of beans, happy horse is an added positive side effect !