HI Richard,
I was considering the same before buying my Dob and decided not to go the collapsible path. These are the reasons:
- I mainly wanted to use the scope at home and don`t have to carry it more than 10m from storage to observing spot
- I wanted an easy set up/move back in less than 2 min (grab and go) with no tools required (incl collimation lasers)
- Costs are much lower for solid tube
- No light shroud required to block out reflections
- Solid tube prevents a lot from happening to the main mirror especially when out in the dark at the EP (beer spills, falling eyepieces etc)
- solid tube sustains collimation for a longer period when scope is moved around
- I can get some tube rings and lift the scope onto an EQ-mount-way easier done than with a collapsible
- a number of people go on about flocking and baffling their scope tubes to increase contrast and image quality - on a collapsible not possible
All this pointed me eventually to a GSO 12".
I think, unless you need to collapse the scope because you wouldn`t have sufficient space otherwise, it is not necessary to pay the extra money for the facility.
Having said that, above 16" I wouldn`t be to sure about the above as such a brute becomes increasingly different to handle and doesn`t really fit into any car.
Hope I could give you some arguments to think about!
Max