I shoot Fuji Sensia 100, a consumer-version of Astia 100F, a lot. I really like the low contrast and natural colour rendition that is not warm nor cool. Especially the highlight area (is it called "toe" in slide film?) is long, so highlights don't blow up so easily as they do with Provia; you don't have to err on the underexpose side so much, and it will give you more "negative film" look.

If you want even lower contrast, you might want to try rating film one stop slower and pull processing. But, you have to try it with the particular film you are going to use. I have tested pulling and can recommend it with Velvia 50; it will give overall lower contrast both in the shadows and hilights as well as midtones.