I've bought quite a few ph pens in the last 15 years. Expensive Bluelabs and Hannas, etcetera. The best pen I've ever had is one of these.
I was going to just use it as a standby, but it has lasted two and a half years now and still soldiers on. My Bluelab, on the other hand, took a shit in six months, and my Hannas never made it a year without new electrodes... which cost more than the entire cheapo pen does. If you want to treat yourself to a fancy expensive meter by all means do so. But in my experience it's really not worth it.
Here's the thing: ANY piece of shit ph pen will work just fine, unless you have automated your system and need constant ph monitoring. The only thing you need to be sure to do is quickly check to see that it is still calibrated. I do a quick dip into 7ph testing solution to make sure; it takes less than 30 seconds. It stays really consistent and accurate with this shit-pen. I make a slight adjustment every few weeks via a screw in the side of the meter.
TL;DR: if you put a crappy ph pen into calibrating solution and it says 7, it's just as accurate as a Bluelab that says 7.
Just my experience. YMMV.