I decided to contact Gillette to find out what the difference is between the Custom Plus 3 and the Sensor 3. I also asked if they would fit on the Sensor handle. Here is the response:
"Thank you for contacting Gillette.
The only difference between they are two different products and the Sensor3 Sensitive Skin disposable razor has more lubrication on the lubrastrip. These systems are disposable and they do not fit on to any of our permanent razor systems.
I hope this helps."
I think I failed to mention in my original email that the Custom Plus 3 was also the "sensitive" model. So, therefore, there is no difference between the Custom Plus 3 and the Sensor 3, except of course for the price. The Custom Plus 3 are a little cheaper than the Sensor 3, about $.05 per razor. Not a significant difference.
Also, even though the Gillette representative states the razors do not fit on to any of their permanent razor systems, she is wrong. They both fit nicely onto the Sensor handle.
I stocked up when Gillette had a few $2.00 off coupons so I will be good for a while, but up next are some BIC Flex 3 that I picked up for about $0.50 a razor. I will report back in two months after the testing is completed.