What Consumer Medical Device is The Best Form Factor?

I’ve been thinking a lot about the various form factors that are being used by consumer medical device companies lately. I think this interest was sparked when I heard a couple of the following statements:

“We’re about to enter a real battle for the wrist.”

“One of the keys to broad adoption is to build a product on top of an existing habit.”

The first statement really highlights the number of wrist based monitoring devices that are on the market. I agree that there’s going to be a real battle for the wrist. Interestingly enough, the second statement highlights why there’s going to be a real battle for the wrist. Many people are use to having a watch on their wrist. So, a product that is on the wrist is building on people’s habit of wearing a wrist watch.

What are your thoughts on the various form factors that are being used for medical devices:
-Wrist Bands
-Chest Straps
-Pant Clips
-Shoe Clips
-Arm Straps
-Head Straps
-Hand Held
-Pocket Stored
-Full Shirt
-Full Shorts

Are there any other form factors I’m missing? I’d love to start a real deep discussion on the various form factors and the pros and cons of each.