I've been in 2 weddings and loved both dresses.
I was the only attendant in one wedding and got to choose the dress myself with no restrictions, so it was a simple after-five black dress that I wore many more times.
In the other wedding, the bride chose the dress: beaded sleeveless bodice with lightweight flowy skirt, all in midnight blue. All 3 BMs loved it. After the wedding, one BM had the dress shortened to just above-the-knee and continued to wear it, and one BM removed the skirt altogether and wore the bodice as a fancy top. I had originally planned to shorten the dress, but I already had to alter it for the wedding into a maternity bridesmaid's dress, and never felt like undertaking the task of re-altering it back to something I could wear again.