I run with two snipers in my squad, (one going down the left tree, one going down the right tree), and I must admit I enjoy Snap Shot much more.
Squad Sight is just so *terrain* dependent. If there is no high ground, or you're entering an alien ship...all you can do is have an Squad Sight sniper sit back in regular cover, Overwatch, and hope something lines up.
Snap shot works well with your group being mobile though, and if your Heavy is using holo targeting it should help make up the difference.
I think the point of snapshot is to turn your sniper into another front line attacker. Higher range but lower accuracy. Hence, only useful in twisty maps. There aren't many twisty maps late in the game. If you need that then gunslinger is better anyway, attack of 7 + infinite ammo.
The difference in kill count between my Snap Shot sniper and my Squad Sight sniper indicates otherwise.
Skeleton armor compliments squadsight so well. I don't know why anyone would have a snapshot with more kills unless he/she was brought on more missions. Double Tab and In the Zone both compliments squadsight as well in my opinion
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Early on I was always annoyed when I had to re-position my Squad Sight sniper, since it effectively made him useless for the round, so when I leveled my next sniper I went with Snap Shot instead. Now that I'm farther into the game I really wish I'd taken Squad Sight on him, as my original sniper routinely decimates the enemy.