The VO and Pletscher are different designs and on my bikes both interfere with crank rotation but this is not a concern to me as I do not try to use the center stand as a maintenance stand other than for puncture repairs. The main similarity between the two stands is that both have articulated arms. I have not read that use of the Pletscher on a loaded bike was not recommended. Certainly I would not sit on the bike with the stand down with any bicycle center stand.
The Hebie aluminum stand I have installed on one bike does not interfere with crank rotation but does stick out to the sides considerably more when folded than the VO. The Hebie is no better at holding the bike upright while cargo loading than the Pletscher or VO stands though.
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Gear Hubs Owned: Rohloff disc brake, SRAM iM9 disc brake, SRAM P5 freewheel, Sachs Torpedo 3 speed freewheel, NuVinci CVT, Shimano Alfine SG S-501, Sturmey Archer S5-2 Alloy. Other: 83 Colnago Super Record, Univega Via De Oro
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http://groups.yahoo.com/group/Geared_hub_bikes/