Teleporter if it's a defense map where the trek is long, generator for when the objective is just next to the spawn. The reason she even has the generator is because she wasn't a good pick for the latter.
teleporter on point A
if there's like 30 seconds remaining and the enemy team is grouping up for a last push I put up a shield gen for extra 75 regenerating health for all instead
If your spawn is close, like defending point B on Temple of Anubis, Shield Gen. If your spawn is far away, like defending point A on Hanamura or Volskaya, then Teleporter. Situational awareness yo.