Just bought a ProAm DVC250 Camera Crane and did some testing. The crane is made of aluminum and is quite solid, the tripod witch is also made of metal, is still not very stable under the weight of the crane and counterweights.
The crane performs well but is a bit wobbly when stopping or changing direction.
Overall, the Crane works well and is a good investment for it's value !
The optional electronic Pan & Tilt head is performing very well and makes the unit into a very usable item to get those special shots you might want.
I needed around 15Kg of counterweight to balance the Nex-Fs100 and the stock lens on this crane. After balancing the unit it performs fantastic and handles with one hand. The Monitor is a great help together with the extension LANC cable witch i'm using with the original start/stop remote from the Nex-FS100. I'm using a long HDMI cable and splitter to get the image out, both to the monitor and my Ninja.