I've had one for around a year or so, love it. I liked it enough to buy the Dosetronic to dose based on the Alkatronic's readings. Reagent is fairly inexpensive and close to free if you DIY. I haven't replaced any parts yet, everything still works great testing 8 times a day.
The only thing I'd change about it is the sound, it's the loudest piece of equipment on the tank. It's much quiter with the new firmware and quiet kit, but I still hear it if I'm in the room and it's testing. It's quiet enough where I don't need to change the TV or conference call volume, but it's definitely not silent.