The Proaim Skater Dolly is only good as long as you drive straight. If you're trying to do curves with it, it becomes pretty much unprecise. I have tested it and I can not recommend it.

The best one I have seen on IBC 2011 was one from Konova (there were more manufactures, but Konova performed best). I don't know if it was just a very good sample, but it was able to drive in circles around a center spot without drifting to the side.

BTW: The accessory arm solution for mounting the camera is good. If you need more stability, you should buy a small weight for a dumbbell and simply add it to the centre where the accessory arm is located (make sure it's not too big, else it will block the wheels).

Cheers
Tony

Here's an idea to get more height an infinite adjustment. The arms are from this post.
http://personal-view.com/talks/discussion/71/mounting-your-accessories.-arms.-clamps.#Item_16

Ditto on any flat surface, even vertical walls, round steel poles, street signs, car roof/hood etc, so quick and easy to get a steady motion effect and fits in the suitcase for travel.

good for table top shot I reckoned.

I find my self using a skater dolly the most out of the slider and jib that I own ..I like that its compact and nearly works on every flat surface ..The one you posted here looks great

@Rambo

I know about it for long.
Idea is interesting, but approach has numerous flaws.