To add some perspective to comments made by Ye Olde Pilot et al, 1. Some pilots don't have any choice regarding what they can wear as this choice has made for them by the company they work for. 2. I would guess that over 50% of small to mid-size heli ops around the world are operated by crews who do not wear uniform so its not such a rare thing. In the US the majority of small operators wear regular clothing. 3. In certain situations/locations wearing a uniform can be helpful.
VF, you might like to read
these comments about the C20R conversion for the 206.