Some of your comments seem a little unfair. Pentair SWG reliability seems to be in line with all of the other major brands of SWG. There is no indication that they require any more service calls or any more parts replacement than any of the other major brands. The cells do cost more to replace, and there is the steps of 20% issue, but those are the only issues that seem to come up regularly that are in any way different from other brands. If anything the Pentair units have perhaps been a tiny bit more reliable than the average SWG recently, though they did have a run of problems a few years ago.
You may be right. I'm going off the experiences I remember. Chances are if they were working fine, I'm not going to remember those instances. Only the bad experiences tend to stick. However, I've never had to deal with a bad temp sensor or a bad flow sensor in an EcoMatic or a Compupool SWG, but I have seen multiple issues with Intellichlors. Don't get me wrong, both the EcoMatics and Compupools have their shortcomings, but their simplicity limits the potential for problems.
That being said, I think my comments are fairly reasonable. If a sensor goes bad, chances are it will happen pretty close to how I described it above. In a more simple system, it is often easier to troubleshoot and repair. For example, with the Ecomatic systems, I would say 90% of the time, problems are due to poor connections at the cell. Wiggle the wires, and you are back up and running. If necessary, you might need to clean or replace the connector. This is a pretty easy fix and will cost less than $10. Simple system=simple fix. Other than that the only other issues I've seen are the occasional blown fuse.
With the Compupools, I honestly can't think of a time where I've had an issue, other than cell cleaning. This of course excludes systems that failed under a recall, in which they were replaced at the expense of Compupool.
I work primarily with the EcoMatics and Compupools, as that is what the company I work for installs. I see hundreds of them, and I have an overall positive opinion of them. When it comes to the Pentairs, I see a handfull of them, and somehow out of that sample, I have seen more than enough problems that became expensive and involved fixes to have soured my opinion of them. To me, that says something.
To be fair, the Intellichlors are not the only systems that I have found to be problematic. I've seen similar issues with Autopilot systems as well, and its usually a result of a more complicated system offering more opportunity for things to go wrong.