Plastic figures have revolutionized the hobby. 3D printing is next. I don't like the assembly stage with plastics, but plastic figures do allow great flexibility, and potential for fantastic diorama displays.
I just have a few samples of these Persian figures. I am overwhelmed with lead figures going back to the 1970's. I do agree with some commentators that the horses are a bit large for ancient times. They seem more tuned for a heavy Cuirassier than a Persian horseman of the Greek wars. Persians did have larger horses, Niseans from Ferghana region in the north east. But these were a rare breed, and probably kept by the Great King as a Royal herd and doled out as rewards to loyalists.
That being said these figures are well executed and are a great place to start for a Persian force. Sadly these figures as well as Wargames Atlantic's figures just cover the Persian themselves and there are huge gaps in creating the multi-national soldiers that comprised the Persian hosts. When one reads the accounts of Marathon, or Plataea, or Cunaxa, one asks "where are some Sakae that fit with these?", "Where are the heavy cavalry with horse armor?", "Where are some Asiatic troops with different leggings?".... to answer that question one has to do a deep dive into other ranges and go into the time travel machine to find them. (Note the Footsore line has been releasing some of these pertinent allied figures for their skirmish Mortal Gods game).
But if I was new to this, I am fairly sure this is where I would start. But also look at the Wargames Atlantic Persian foot as they have some nice figures that may look more like Immortals from the classic Monvert book on the Persian Army by Duncan Head.