Yea, this isn’t a question anyone can answer for you except yourself. Redheads or Blonds? Rocky Road or Chocolate Chip? It’s all a matter of preference.
Do you know what the roles would be at each company? There could be huge differences in your involvement in real engineering. Often the longer duration positions get into more engineering so that might be a point in favor of GE.
Typically a 6 month co-op will give you a better chance to learn and become productive. (There may be tuition credit to pay for.) But… often it is easier to make logistics work for a shorter internship.