I found Moab Lasal Dual Semigloss to have excellent image quality for a luster double-sided.
But I much prefer matte for my hand-made artist books. At a 15" viewing distance with no glazing in the way, matte papers invite lots of light and close inspection without glare. Moab Lasal Matte is a perfect weight and beautiful image (see attached). Red River Arctic Polar Matte Double-sided is nearly identical weight and image quality and offers more sizes and guaranteed grain short (can be really important for books). Both Moab and Red River offer sample packs. And both offer a luster / semigloss as well as matte of (nearly) the same paper for you to compare gloss to matte.
I support Mark's Hahn PhRagDuo recommendation for a beautiful paper. At 277gsm and 17.7mills, however, it's thicker, denser, and stiffer than the Lasal or RR papers (which can be problematic for some books), and it is 5x the price: $3.96 per 11x17 sheet vs $.91 for Moab and $.70 for RR.