I use the MB stand. I found it to be the cheapest available. It rolls on smallish locking castors. It has straps and a good cover. It requires care when moving over bumps and cracks and so on, but my driveway and stable (in which I keep the hardtop when not on the car) are very roughly surfaced. It has never really threatened to topple.

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JJ Rodger
2013 G350 Bluetec
1999 SL 500
1993 E300 diesel T
1990 190