hou.TX
Welcome to TFP. In my opinion, you have come to the right place to get your questions answered.

Since the IntelliCenter topic has come up, I'll just throw in my two cents since I have been using the IntelliCenter for my pool automation needs since December 2018 now.
1.
The IntelliCenter Server. There were some server problems that occurred over about a 3-week period in May/June of this year. It was very frustrating for many of us and especially for those that were right in the middle of configuring their brand new automation systems. The way the user typically connects remotely to their IntelliCenter involves using a desktop/laptop connected to the internet. The IntelliCenter is also connected to the internet and the Pentair servers and there is where the connection is made and where a user can run into problems. Normally this connectivity scenario works just fine. But, there are advantages TOO!! Firmware updates to the system are fairly seamless, especially compared to other Pentair Automation Systems. Those IntellliCenter updates are called Over-the-Air (OTA) updates. They are downloaded and installed directly from these servers to your control panel at the pad through this internet connection. That is 1000 times easier and a lot less costly than the way that the other two Pentair automation systems get their upgrades which usually requires sending the board in to have it flashed, paying someone to come out and do that or buying a new motherboard. This is important as the IntelliCenter is now considered the flagship of Pentair automation. So efforts to do automation product improvement are going to go to the IntelliCenter and not the other two automation systems.
2.
And here is the good news. Although there has been some issues with the IntelliCenter server recently, you can still connect "locally" through your own network via your handheld mobile device such as
@jimbethesda was explaining. No server or outside internet service required. Once someone has their system configured, this is usually enough to do whatever the user needs to do and of course if you trip and you and your iPhone go flying in the pool (contrary to popular belief, iPhones are NOT waterproof), then you can always just dry yourself off, throw your iPhone in the garbage can and walk over to your pad and do whatever you need to do from the touchscreen.
3.
User Interfaces. Just a small correction to one of the things that
@jimbethesda said above.

Actually, I do
NOT prefer the web
app (I rather wish is was an application lol..) client. I'm not a fan AT ALL and I have wrote about the disadvantages and pitfalls regarding the IntelliCenter web client ad nauseam, here on TFP. I will say however that in my opinion, I find it a whole lot "user-friendly" performing initial setups and configuration on the web client versus a mobile application such as on an iOS or Android device. But after the initial setup and configs, the mobile applications are just fine and are typically preferred for normal day-to-day operations.
And there are alternatives to the Pentair web client (and the Pentair Mobile apps) that are only now being developed and refined. There are several threads here on TFP that explore these possibilities. These alternatives are for those that will no longer accept the clunky and buggy Pentair solution to a user interface. I am one of those. Just let me ask you.
Would you prefer this (where you are beholden to the whims of both the Internet AND the Pentair servers)?
Or this? Which is up and operational 24x7 as long as your local home network is up. The below solution which I use now works in about the same fashion as do the other two Pentair "ScreenLogic" based automation systems.
3.
Macros. Here is the one area that really sets the IntelliCenter apart from the other Pentair automation systems in my opinion. Macros are not necessary for simple pools (although they can still be useful), but they are "game changers", when a users pool is anything more than just a pool (no spa), pump, heater and SWCG. But for any pool that has an associated spa, water features, bubblers, advanced schedules, advanced lighting features, etc., then Macros make automation programs, configurations, scheduling and operations a breeze. One command and lots of things can happen at once.
One of the Pentair automation systems do not feature macros, another one does but it is a real pain IMO to setup and program and the IntelliCenter macros are very easy to setup. To the point that they are fun to setup and very flexible and you can get very "creative".
I hope that I have provided you with some information to help in any decisions that you face regarding your automation needs and requirements.
Stay well.
r...