I use both, though almost all the hanging has been with a Size Doctor bell instead of a bell and sleeve. The Size Doctor is quirky and hard to use, and getting out of it can be downright painful when I need a pee break. I did an hour of hanging with the TM bell today, and it was convenient and comfortable. I only used 1-1/2 pounds, though. I’ll step it up in a few days.
I’ve been trying to increase my extender time in the hope that it’ll help stretch some skin, which has not kept up with my length gains.
Many companies sell the same bell and sleeve with different accessories as a hanger, extender, or all-day stretcher. You can get the most tension as a hanger. Configured as an extender, you’ll eventually get pinching between the base ring and the pelvic bone, which limits either the tension or the duration. An ADS is basically light hanging without weights, using something stretchy to provide tension.
As a general guide:
Hanging, you’re (usually) stuck in one place, but tension is high.
Extending, you’re mobile, if privacy isn’t a big issue. Tension is moderate.
ADS, you can (often) go out in public, but without as much tension as the first two. You *can* crank a lot of tension in, but walking or sitting can then be a problem.