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I can say they don't hold primary mirror colimation well because the mirror cell is support by ****, flimsy springs.
If you get one. Replace the mirror springs with something beefier like a compression springs from Bunnings. You'll have to grind them in half so they will fit back in the cell. The goal is to get springs strong enough so that you can throw away the locking screws in the mirror cell and just use the tension of those springs to hold the mirror cell in place.
Collimation is then easy. You tighten up the collimation bolts all the way the first time. Then collimate the primary by loosening each collimation bolt. This technique does push your mirror cell forward.
The good part of this that when you go to setup collimation the next time you use the scope only a very minor adjustment is needed.
Pair that with bobs knobs for the secondary and adding a few milk bottle washers to the mirror/secondary stalk and collimation is an under 60 second job for me even after traveling from Sydney to the Blue Mountains for a dark sky session. Only a couple millimeters of adjustment at there primary mirror is generally needed.
My 12" truss dob folds down to under a meter in length. The original base is heavy at over 20 KG. I rebuilt/replaced mine with marine ply. Knocked off about 9 KG. Solid a rock though. Setup is under 10 min - including collimation. Mine only came with 1 dust cap. But a I made another out of plastic that sits practically on top of the primary mirror. - It seems to help.
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