I've had a jebao dp4 for 3 years and honestly i think its the best bang for the buck you will find out there. I've never had it dump a whole container of solution into my tank which is the main thing I worry about. It was pretty easy to calibrate in the beginning and I have not calibrated since. How does the calibration hold up? I have no idea, and frankly, I dont think it makes a difference at all. I try to test my water at least every month and at those points I make adjustments to my dosing amounts whether the levels are trending up, trending down, or staying where I want them. In general, I tend to add a bit to the dose amount every month or 2. Is it because its losing its calibration...? Maybe. Is it because my SPS are growing and requiring more elements....? Maybe. Frankly, it doesn't matter which of those causes is the reason, you should be testing your water with some sort of regularity and you will be able to adjust the dosing as needed. At around $70 or less, there is nothing on the market for a comparable price that will give you 4 heads at that price.
With that said, I'm planning on getting a new dosing pump this year during the Black Friday sales. Most likely I'm planning on going with either a DOS (make that 2), or a GHL. Why? Mainly because programming on the jebao involves a lot of smashing buttons with my fingers. I would rather program things remotely on the computer. I will likely keep the jebao and use it to start dosing my other additives like acro power, potassium, and strontium.
Also speaking to durability of the jebao, again I think there is a lot of variability between individual units, but I have been dosing in excess of 100ml per day split to 4 doses per day on 2 of the pump heads for the past 2 years at least. Although the heads are getting a bit squeaky now, they still work fine.
