interesting! Any opinions on these various films?
Speria Premium 400 appeared in the domestic market a while after Kodak released their Ektar. The most conspicuous feature of the Premium is its finer grain for its speed, I suppose. Its colar is not as crispy as the old Venus series, while it's not as natural as the Reala either. My feeling towards this new film is something like a finer grain version of Kodak's Gold 400 with Fuji's color rendition. While you may have difficulties in finding the other 4 films, you can find this Premium anywhere (local camera store, dugstore, supermarket etc.)
People here often say the Senisa III is the consumer version of the Astia. But I think they are different in many ways. I have very limited experiences with this RA3, but I think it's got even more natural and warmer tone than the Astia.
Trebi100C was another consumer version of Fuji's slides. The emulsion itself seems very similar to the Provia's, but as it uses clear film base, it looks more saturated and contrasty. As this long beloved Trebi has finally been discontinued in June, you may have difficulties in finding one in coming December.
Though I fogot to include in the previous post, Fuji's Pro400 seems another film that is only sold in the Japanese domestic market. It's Fuji's only pro-line 135 print film in Japan. It has moderate saturation and tone with its color adjusted to suit the skin tone of Asian people.
I usually shoot Kodaks, both slides and print films. So, my opinion is based on very limited experiences, but I hope it helps.
Luno