First of all, I'll confirm what others have said: it's solid, does the job and is much cheaper than similar products available on the High Street!
I used mine to mount a Sony KDL32D3000 and it went up no problem. The spirit level on mine was pretty accurate, so no complaints there. The one criticism I have is that the tilt mechanism is rubbish. My TV weighs about 20kg and no matter how much I tightened the tilt-locking bolts, the TV just flopped forward to the maximum tilt, which in my case, was way too much. I solved this by inserting an additional nut and bolt at each tilt point so that I could limit the maximum tilt and I'm pleased to say it worked a treat.
Although the tilt mechanism might work for TVs weighing less, it simply failed with mine. This failure is the reason I've given four stars. Other than that, it really is a solid, effective and cheap solution to wall-mounting your TV!
p.s. If your TV isn't 100% level when it's mounted on the wall, put some kitchen tin foil under the lower of the 2 TV brackets to balance it off. It's much quicker and easier than starting all over again!
p.s.s. If you're concerned that mounting your TV close to the wall will damage your HDMI cable, you could buy a right-angled HDMI connector or a Panasonic Free-Angle HDMI Cable (each end of the cable terminates in a 180 degree swivel-head so that the ends of the cable don't have to bend to fit into small gaps i.e. between the back of your TV and wall). I bought the latter and it works brilliantly!