I have been using my Apera for more than a year now, hundreds of readings. Every time I have checked the calibration, probably ten or so times, it has been within 0.05 ph or so, which is close enough for me. I rigorously prevent the probe from drying - it is either in storage solution or it is in test solution, never in air for more than 20 - 30 seconds or so, usually less. I store the probe in 3M KCL solution that I make myself. Cheap, and apparently effective. The commercial storage solutions are a rip off in my opinion. I change the storage solution in the cap regularly to keep it clean and undiluted.
So far, I could not be happier with the Apera. It also has a replaceable probe, so when the time comes, getting it back in business will not be expensive.