I've been using this paper for a few weeks now and here's my latest thoughts on this paper.
Quickly glancing at images, the paper looks fantastic, with blacks deep enough to dive into and smooth tone gradients and subtle highlights. It doesn't require output sharpening and the images really do look like they were made in a wet darkroom, from 4X5 (all be it in 8.5X11 prints). On further inspection, the gloss might be just a tad too shiny - it's a little tricky finding a position to hold it without some reflections. For hand holding prints, this isn't really a problem - for mounting on the wall, well it might be - haven't done that yet so it's pure supposition. On my iPF5000 and selecting a custom warm tone in the monochrome printing - the results are absolutely lovely - warmth without a hint of pink or green and no signs of metamerism.
I can certainly see using this paper for portfolio presentations as it really does show off the images to their absolute best. Today I found that Booksmartstudio has just put up an ICC profile for the paper and the iPF 5000 printer and I was able to use Paypal to fork over $4 for the profile - a bargain! I haven't used it enough yet to know just how accurate it is, so far so good.
Production quality is superb - the best of any of the 'glossy' papers I have tried so far - not a marred sheet or dinged corner yet.
Pure whites do have slightly less gloss than the rest of the image - but this is slight and frankly not a big issue - I am happy to sell prints on this paper.