You know I just recently figured out that you're the person who is following my blog. Or maybe I'm mistaken?
Amira hijabs are sewed up so that they just slip onto your head - no pinning needed. They are exactly in the shape as you see in the pictures - you pull it over your head, and it just sits there and the rest falls over your shoulders.
I personally don't usually prefer amiras because some may be short in the front, and don't provide adequate coverage, but they are very neat and not bulky. I love them though if I'm wearing Shalwar Qameez (Indian dress) where there is already a separate scarf to drape in front anyway.
In contrast, long rectangle pashminas can be worn in any style you prefer, and you can pull it down in the front. I would say that its personal preference, and at least everyone should try both options out and see which they like.
The amiras I got from Middle Eastern Mall are pretty long in front so I really like that aspect about them.