Define YOUR Requirements
Pat - The great thing about forums like this is that you can post almost any question and get answers. But you should filter the answers to find the ones relevant to YOUR situation.
My advice to you is to spend some time thinking about YOUR requirements. Make some decisions about what type of hollow forms you plan to turn - fat and squatty, tall and narrow, wide or small mouth/opening, etc. After defining YOUR requirements, filter the inputs received on this thread to find the ones relevant to YOUR needs. Some thoughts/comments may not be applicable to YOUR needs.
Everyone likes what they have - Jamison, Monstor, Oneway, Carter, Gizmo, etc. That's why they bought it. They thought it was the best hollowing system for THEIR needs.
I have a homemade Jamison look-a-like. It's simple. It was inexpensive. It meets all of MY needs.
I suggest you find some folks in a local turning club that have the various hollowing systems. Have them get in touch with you next time they are going to do some hollowing. Visit their garage/shop/studio and check out the system they use. - John