I've put up 3 of these and they are very nice. We use them for hanging up our kids artwork.

Here is what you want to watch out for installing them though... it is tempting to tighten the cables to the point where they are very very taught but if you overtighten in drywall it will mess up the wall. I did this on the first one I put in. It caved the drywall in a little at the outside of the round base. This is in spite of it being secured to a stud.

I ended up cutting little squares of wood, staining them and using them as a sort of base for the metal cable-holders to go on. This not only covered the caved in area of drywall, but also looked pretty nice. It had the added benefit of allowing a more secure hold to the stud. Because the holes for the bracket are arranged in a sort of triangular shape, you can only reliably get one hole to hit a stud. Not the greatest for the base to only have one good anchor point in my opinion. The little squares allowed me to put 2 screws solidly into a stud and then the base has plenty of holding power screwing directly into the wood.

As far as tightening, just tighten it barely enough that you can pluck the wire and it like a guitar string or something. The wire doesn't have any flex or give, so any tighter and the flex will come from your drywall.

Looks great when installed but the install is a little tedious. The wiring can get easily frayed because the small plastic end coverings that hold the wire together are not durable and the wiring does not fit very well.