Welcome to the thread - seems like it is just you and me here right now. Having asked the question early on, I now realize it is too open ended to actually get much help from people. As a result, I have started to ask more directed questions.
I too am in MD, I am in Bel Air in Harford County. I am looking at 4 pool companies:
Anthony Sylvan
MD Pools
Catalina Pools
Elite Pools
My land is not flat and right now I have an easement in the back yard that is limiting both my pool size and my pool location. Working with engineers and the county to get it removed. Will need to select a PB before I can trully start to investigate the implications of my grading issues because they have all resisted putting much if any time into shooting my grading and designing with it. Pretty sure, my land grading will cost me time and money to overcome.
I have spoken to all four companies, but have only met in person with 3. One is almost certainly out of the running since they missed their first and easiest deadline and have ignored one email and one phone call.
I am very much evaluating the others.
So far I am looking at a heat pump for a number of reasons. I have been told that they are very efficient at maintaining the temperature, but are less efficient than gas heaters at raising the temperature. Given the use of the auto cover and the hot summer days we have in MD, I am comfortable with the trade off. I am even thinking of adding a cooling option to the heat pump since I am a little worried that the combination of MD summers and the auto cover will get the temperature too high to be refreshing.
I am looking at SWGs, but the only ones I have trully looked at are Nature 2, Bioguard Mineral Springs and Auto Pilots Total Control System. I have pretty much eliminated Nature 2. The Bioguard Mineral Springs system appears to be a good SWG, but is very expensive to buy their proprietary "renewal" bags. If used as a traditional SWG, then it appears to compete well against the others, but the "renewal" bags are expensive and don't appear to adapt well to changing environments throughout the season. The total control system is a good SWG, but I would use it only if I was going to upgrade to the entire system for PH and Acid dispensers.
I have started to investigate the Pentair Easy Touch 8 system, but don't trully understand how it fits in with everything else.
I have looked at VS pumps from a very high level.
I have looked at filters from a very high level.
I have spent some time looking at overall plumping and pad design, but feel very overwhelmed. One PB I mentioned it to, pretty well cut me off and said something like "we will design the plumbing to be exactly what it needs to be". Either he's guarding against his lack of knowledge or he figured out mine and didn't want to waste his time. Either way it left a sour taste in my mouth and I have a lot of work to do on this topic. Reading Hydraulics 101 certainly didn't help with my confidence

At a very high level, the recommendations I have heard from the board include 2+ inch diameter pipes for all plumbing except for the returns to the loop where we would use 1.5 inch piping.
I have also looked at the main drain problem (where hair or fingers or bowels get stuck in the plastics or the suction and people drown or get eviserated). It seems the only true solution is not to put a main drain in - although this is somewhat non-standard there are lots of people and lots of builders who have gone that direction. From what I have read, one or two skimmers is sufficient for water circulation when combined with returns. I have thought about putting in a main drain with a valve in the plumbing that allows me to control it from 0-100% so I can close it whenever anyone is swimming. I have also looked at VSRS systems (Saftey Vaccuum Release System) where the pump will shut itself off automatically if it gets blocked. I have been told that some VSRS systems are very hard to reset and would involve a call to a professional service company where some are very easy to reset and can be done by the pool owner. More research needs to happen here.
I actually do have a spa already built into my deck so I won't be adding one to the pool build. I have ordered the TF100 test kit and plan to learn BBB using the spa and the testkit. Hopefully, I can get exposure to it and get comfortable with it well before the pool is built (or ground even broken).
My timeline right now is for next season - unfortunately the easement has thrown a major stumbling block for me and will take weeks or months just to work through it. By then, the swimming season will be almost over and it doesn't make much sense to rush for a couple of weeks of swimming (at most).
We should stay in communication just so we can leverage each others experiences and knowledge especially since we are in the same state and are looking at very similar builds.