I wanted a pH memter for my allotment and after research got this one. You can't place it straight in the soil but have to put soil in a container, add some distilled water (I got a large container from Halfords) mix then put it in but it is more accurate than many cheaper uncalibratable models you put straight in the earth. You have to buy buffer solution and keep the sponge in the lid moist with it to keep the probe damp and store it upright, and I made a jam jar of pH7 solution to check calibration and recalibrate when necessary.
An update in May 2014 to say that it is still working well, I just have to ensure it's stored upright so the sponge doesn't dry out. It lives in my shed and I spray the probe with distilled water in between readings.