I love the colour of this dress, foremost. I also really like the length - it would definitely be suitable in a professional environment. The length of the sleeves add to this, too.
Without the belt I felt this was slightly too long for a casual look on me, so I added a wide stretchy belt. I like how the cobalt looks against the black. I also like the wide neck, it's great for me.
I was given this dress for free but you can get it for $40 on the website.