A Tube Birdfeeder: Perch or Cling?

For attracting Goldfinches with Thistle or Nyjer seed, both types of feeders work well. The advantage to a clinging-type feeder is that more feeding space is available, you’ll likely see more birds at the feeder at one time.
If you’re looking to attract multiple species with Black Oil Sunflower seed for example, a tube feeder with perches will allow each bird its own space.