I recently purchased a new 42" plasma TV for my living room: the Panasonic TC-P42X1. I bought the TV with the intention of hanging it above my fire place, but was shocked to find out that an articulating mount at Best Buy was $300! So I did what any sane, sensible American would do; I told Best Buy where to stick it and went to browse on Amazon.
After some consideration and reading all of the reviews for various mounts, I decided to go with this Cheetah two-arm articulating mount. Not only was the price less than half of the Best Buy mount, but I also liked the idea of two arms holding my brand new TV.
So I got the mount and found that it was really easy to install. I don't see what all the fuss is about with the directions being "difficult". I think it helps if you have a technical mind (I'm an electrical engineer) because I had no problems with the directions at all. There are no assembly pictures in the directions, so if you are a visual learner, that might be why it's difficult.
Now, on to the mount. It's of very, very, very solid construction. It is made completely out of a steel frame and steel hardware. I had no trouble hanging the mount on my wall studs (and yes this mount is made specifically for 16" spacing, but can go up to about 18"). I would recommend picking up some new lag bolt hardware to hang the mount on the wall, though. I got some 1/4" lag bolts with lock washers from Lowe's pretty cheap. I would also suggest getting a second pair of hands to help you mount this beast. It is quite heavy.
I would also recommend tightening all of the hardware that comes pre-assembled on the mount BEFORE YOU HANG THE MOUNT. I say this because I did not do this and I noticed that one of the bolts that holds the arm was on its way to falling off after I had the mount on the wall and the TV hung. And it's rather difficult to get on those bolts and give them a good torque-ing.
But the action of the mount is fairly smooth. It is a little difficult to move the TV where you want it, but once it's there, I have no worries about it falling down. And the range of motion is superb for my use. I'm able to swing the TV screen approx. 60-70 degrees in either direction.
Now my one complaint about the mount (and the reason behind the 4.5 of 5 stars) is the way the TV sits on the mount. The mount comes with two brackets that attach to your TV and then the TV hangs on the mount via these brackets. The only thing that holds the brackets to the mount is the weight of the TV and a metal bar that runs along the bottom of the brackets to keep the TV from tilting off. This would be okay if I wasn't moving the TV constantly, but I find that with this setup, whenever I push my TV back flat against the wall it always moves a little bit on the mount. It's a little unnerving and a little annoying too since I like the TV to be in the center of the fireplace.
Other than that, the mount is very solid and I would certainly buy one again if I needed to get an articulating mount.