Astia, without a doubt.
There is very little I like about the modern Ekta replacements/versions from Kodak, starting with the price.

As for other things:
Unlike what "conventional wisdom" claims, grain in Astia is smaller than even Velvia's. And that is something I have verified many, many times.

As for saturation and shadow detail and contrast control, this is Astia:
http://wizofoz2k.deviantart.com/art/...lope-108901318
http://wizofoz2k.deviantart.com/art/...lash-101163354
http://wizofoz2k.deviantart.com/art/sugar-buzz-98843762
http://wizofoz2k.deviantart.com/art/...escue-98461919
Click on images for bigger. I'll put any of those against anything Velvia or Kodak, of which I have examples in my gallery as well: it won't be far behind.

As for good behaviour in scans, all of the above were scanned. It is one of the best "scannable" films, nowadays. Much better than anything I've ever seen from Fuji with the possible exception of the new Velvia 50. Kodak's stuff is also easy to scan but the results in terms of saturation, contrast control and colour balance are nowhere near what Astia does.