i will give you my opinions of the hindsight. keep in mind that i have not used it in hunting situations.
Do the crosshairs block your view of the animal/target much? They seem big.
i had this very concern also before i bought it. i really don't think it will be an issue for me. i've drawn my bow with it installed and looked at my target from varying distances and i never felt that it cluttered my view. since this is sort of a personal preference kind of thing i would suggest drawing a bow with one on it to see for yourself...what doesn't seem like an obstructive view to me, may very well be to you.
How well does it show up in low light?
this i can assure is of no concern. i installed the hindsight on my bow. the first thing i did after it was installed, was to take it into a really dark room...man, those crosshairs were friggin bright! for morning hunts i will probably just shine my light on them for a few minutes before i head out to my stand...i would suggest go to the hind sight website for additional info on how long the glow lasts as well as how long the actual glowing material is good for.