It's a very rare workload that performs worse under SMT these days, on either AMD or Intel hardware (or POWER, or any other SMT implementations).
When Intel first introduced SMT on their Pentium 4, there were some workloads that fared considerably worse because both execution threads assumed they should have exclusive cache access, and then spent a great deal of time thrashing the cache, resulting in poor performance. Since then there's been new processor instructions and software development to negate this sort of thing.
There was a recent article on SMT performance on an intel chip at phoronix; in every bench other than VP9 video encoding it was a net benefit (sometimes of the order of 30% improvement)
Intel Hyper Threading Performance With A Core i7 On Ubuntu 18.04 LTS - Phoronix
Zen is a somewhat more complicated beast by nature of its architecture (I can't find a decent on-stop shop review of it but IIRC from some reviews I read, some games and the windows scheduler have/had some problems with its SMT implementation) but overall the benefits are still largely positive for most workstation-esque workloads.