Well, I got the Moab sample pack and tried the Kayenta and Lasal papers. (The Entrada paper is also a fine paper, but about three times more expensive; it could be nice for art prints, but I considered it too expensive for calendars.) The Kayenta is slightly more expensive than the Lasal, but not by much. Both were fine papers for my purpose, and produced slightly better-looking prints than the Inkjetart Duo Brite Matte that I had been using (which I think was a similar price) - they had a slightly less muddy look and slightly sharper edges on text and lines than the DBM (but not a huge difference). The surface texture on the Lasal was similar to that of DBM (which is, not much texture), while the Kayenta had a bit more surface texture that I thought was nice-looking.
I think the Kayenta was maybe marginally sharper than the Lasal, but the Lasal is a slightly thicker paper (235 vs. 205). However, I decided to go with the Kayenta because the Lasal had a slight waviness to it after printing (presumably having to do with the ink sinking in) that the Kayenta didn't.
There was a slight curvature to the 8-1/2"x11" papers straight out of the box, so I'd expect to see some curvature to the larger sheets too. Probably less than I saw with the DBM I used last year, though, would be my guess.
I'm going with Kayenta...
Lisa
P.S. The once annoyance is that the Moab web site suggests setting "media type" in the printer driver to "Ultrasmooth Fine Art" for both the Kayenta & Lasal papers; when you set that, the driver then prevents you from using the auto sheet feeder, requiring you to use one of the single-sheet manual feed slots. Grrrrr. I tried a second Kayenta test print in which I set the media type to Enhanced Matte so I could use the auto sheet feeder, but it came out with somewhat muddier-looking colors, which wasn't great. Unless someone can suggest an override to the manual-feed requirement, I'll be feeding my calendar pages one at a time and grumbling at Epson about it...