Sharpshooter is a long range sniper bot that deals ludicrous amounts of damage at one shot. It takes 10 seconds to reload its rifle.
Helpless against swarms of fast moving units. Always accompany it with some short-ranged infantry like Zeus.
These snipers work best when you have full vision of enemy units, because it can't effectively aim at radar blobs. This is why it works great combined with Infiltrators (spy bots) staying in front of enemy forces.
They require 500 Energy per shot which you need to have in reserve!
When you have sufficient energy you may also make use of its cloaking ability in order to make it less likely to get targeted. These units are very precious and fragile, try to keep them safe.