It depends on your needs and how geeky you are.
A basic unit such as the Aquapure 1400 from Jandy is used by my neighbour and seems to work fine. We both bought at the same time, after 3 years at 10 hours a day, 365 days a year he had to replace his cell, board, and flow sensor, at a cost of $700. But that was after fairly heavy usage. Otherwise it worked fine, I only operate mine 5 to 6 hours a day depending on the year.
I have the Autopilot Pool Pilot Total Control (more geeky), it has the advantage of both temperature control - if the temperature rises it will up the % of chlorine output and if it goes down it will lower it, a great advantage if your pool temperature swings around a lot. One can also add the Total Control box which will allow you to automatically feed acid into the pool depending on what pH you choose, this feature I love as it saves time on maintenance especially if I am in a hurry that day. There are other units that can have this feature added to it. It will also control more than one pump, I think. Obviously these units are more expensive.
I love my Pool Pilot, like anything electronic it has its issues but they are minor, all units have issues sometime. Because mine does have these added features it does require about 20 minutes maintenance once a week. Download the manual and see if you are up to it. Autopilot's tech support is good so long as you get past level 1, ask to speak to a more experienced tech, their replacement policy is excellent and fast. Our experience with Aquapure's tech support was weak when my neighbour and I called.
Finally forget about the ORP feature on some units (mine has it and it is useless in sunlight with CyA in the pool) it really only applies to indoor pools with no sunlight and little CyA in ppm. Well useless perhaps is too strong a word, if you measure the ORP after you have set your time to run on the pump and keep recording say what 4 ppm of FC is you could set the the ORP to say 620 if that seems to be the norm for 4 ppm, but personally I prefer the % method, as do most others who have an outdoor pool, mine is set at 78F at 43%. At 84F it automatically rises to 53%, but my pool rarely gets that warm, unless I turn the heater on for the grandkids. But ORP fluctuates depending on the time of day and the amount of sunlight so what is fine in the morning maybe too low by the afternoon as the cell did not have enough time to catch up by the time the pump shuts down. If you run your pump at nightime then it is more consistent. But as you can see ORP is a little too complicated and % power more consistent.
Also as discusssed in many posts on this site try and buy a cell that is oversized for your pool, something you can run at 40% to 60% power. I think it is Aquapure's manual that writes it is best not to run the cell at over 75% power for any extended period of time. In my pool I have the SC-60 cell running 6 hours per day at a setting of Power Level 2 at 43%, for 10,000 gallons with CYA at 4.5 to 5.0. Perhaps a little bit of overkill on the size but it works great and the volts and amps read like new after 3 years.
Hope this helps.
