The Stipula Etruria is quite larger than the Visconti Van Gogh (or Dali, which is the same model and size).
The Visconti is slender and regular-size, while the Stipula is definitely a large size pen.
Moreover, the Stipula Amber (or Ambrosia, or AlterEgo) is made in celluloid, while the Visconti is resin.
I own a Stipula Etruria Rainbow (acrylic) FP and a Visconti Van Gogh FP. Susanna is absolutely right about the size differences in pens. The Etruria is the largest pen that I own. I don't post it due to its size. It has a noticeably large diameter, so it took some getting used to for long writing sessions. When people notice it, they frequently comment on the size. The Van Gogh, on the other hand, can be posted without looking strange, and the diameter is normal. I wrote with it naturally from the beginning. When people notice it, they comment on the beautiful color of the resin.
Both are wonderful pens. If nib performance is not an issue (they have dramatically different nibs), then I would recommend considering what shape pens you prefer holding, how long you write per writing session, and which you think is more aesthetically pleasing.