PVS-31As are basically the industry standard. Note that there's no on-board IR light, so you'll need to add one to your helmet. The 1531 housing is a compromise, and not worth the added weight over the PVS31A, IMO.
My favorite housing, however, is the Theon Sensors housing which is sold as the EOTech BinoNV or Elbit F5032 (PVS-31D). It has a built-in IR light. Adjustable gain. It will auto-shut-off when flipped up, but somehow, not when you just look up. It will also auto-shut-off pods when they are rotated up and away from your eye. It's not quite as light as the PVS-31A, but it's still pretty lightweight. The optics can focus really close (18"). It has a built-in diopter adjustment. It just has everything you want in a housing. (Well, except for thermal fusion).
YMMV