To be clear, the Spitfire is NOT free-standing. It requires stakes in front and back, and preferably stakes on the sides to pull out the rainfly/vestibule.

Also, there won't be a whole lot of room in either the Solitare or Spitfire 1 for gear. When my son uses his Spitfire 1 he puts his backpack in a large plastic bag for the night and leaves it outside. Many feel packs shouldn't come inside a tent anyway, just to protect it from accidental damage.