Contrary to popular opinion, I use Velvia quite a lot (not tried the new one though). It is very sharp and has great color saturation, but the trick is not to use it in warm settings (like new wood construction or around tan rocks) or last light of the day, as it will get very warm. For those situations and in studio I use Astia, and if I had to pick one film, it would be Astia. BUT - I love Velvia when I can use it. These two are shot on Velvia and have virtually no color correction. The studio shot was done with an unfiltered ringflash, which I did intentionallyy because of the higher UV of a bare flash tube. This is for a 2004 calendar and if you saw the 12x18 test prints you'd be stunned at how sharp they are. I believe the higher UV around water (beaches, lakes, pools) cuts the warmth of the film, because I also use Velvia under these circumstances, and even just on sand or outdoors (again, as long as we're not around warm settings).
BTW, the model in both (a few years apart) is one of my long-time favorites, Pamela Paulshock.
Andy Pearlman Studio