Halotestin has an Anabolic/Androgenic ratio of 1,900/850. Trenbolone has an Anabolic/Androgenic ratio of 500/500.
Gram per gram, halo is such stronger then tren. However, halo is one of the worst steroids you can possibly put into your body in the way of side effects. It is an extremely powerful steroid, but also extremely harsh in the way of side effects. It is extremely liver toxic. I don't recommend using halo longer then 4 weeks without a break. Halo is most commonly used in short 2-3 week cycles pre-contest for it's hardening effects on the physique and dramatic strength gains the drug causes.
For the goals of building muscle, you would be much better off using a higher dosage of tren then halo. Tren is bad in the way of side effects as well, but not near as bad as halo.