The Wraith is best against large-sized air targets.
With the Apollo Reactor a Wraith can remain cloaked for over 3.5 minutes.
The ground attack and cloak make Wraiths useful for harassing the workers of poorly defended expansions. They're also useful for picking out lone units scouting before the opposition can react. Wraiths, however, have a weak ground attack, are fairly fragile against most units, and easily damaged. While this is compensated with the cloaking ability, Wraiths are not very massive due to their cost.
During development, the Wraith was known as the Phoenix. In the StarCraft alpha the craft had a different appearance In the StarCraft beta, while the original name was retained, the craft had an appearance identical to its end successor. Both versions of this craft had Gemini missiles.