Portraits - Formal or Environmental?

After going through the 4th unit of my NYIP Professional Photography Course (Portraiture), I've decided that I don't really like formal portraits. I've proven to myself that I can do them as shown in the photo below.

Although I can do this style of portrait (this one was easy with window light and a reflector), I much prefer to do environmental portraits with natural light like the two below.

The environmental portraits just seem to have more personality to them. The kids are so relaxed and are just being themselves. Now sure these are my kids and they are very comfortable in front of the camera when I'm taking their photo but still, look at the natural ease they have.

Maybe It's just me but I think I may go into Environmental Portraiture as a side business once I've completed the course.

Chris.