As I see it, the Bic Sensitives have the following virtues:
* They're single-bladed.
* They're sharp.
* They're consistent. I never had a bad one.
* Their edges last (a week for me).
* The corners of the blade are proteced by the plastic housing. No nicks under the nose.
* They're ubiquitous (even internationally); every drugstore and grocer has them. You don't have to order them on the Internet.
* They're so well designed that shaving with them is intuitive and automatic. It's hard to screw up using them.
* You can take them in your carry-on airplane luggage.
* They're dirt cheap.
* You don't get attached to them. If you lose one, or an entire package, you don't feel like you lost a friend.
* If you're ecologic-minded, you can dispose of them in the recycle bin; I do.
* You obviate the risk of cutting yourself when changing blades.
On the other hand, the Bics have these weaknesses:
* They look cheap.
* You don't get attached to them.
* You don't get the emotional satisfaction you get when you hold a finely-crafted piece of metal.
I've been shaving for over a half-century. I learned on Gillette Super-Speeds, Schick Injectors, and Gem single-edges. I've played with virtually every bonded-blade, blade cartridge, and disposable, and I've revisited prime-quality double-edge razors. In my experience, nothing gives me as predictable, as safe, or as good a shave as a Bic Sensitive disposable.
For me, if the decision on what to use to shave is made purely on cold and logical grounds, there is no justification to shave with anything other than Bic Sensitives. Using a beautifully made double-edge razor or a straight razor may satisfy the aesthete in you and make the shave experience emotionally satisfying, but on my face, I prefer the Bic.
Bic Regular disposables (white handle) and Bic Metal disposables (black handle) don't work for me; they leave me bloody.