My 2014 S has air suspension and it's working well. Once, however, I loaded up the car with lots of heavy things and left the car full overnight. The next day the car complained about the weight and refused to move. I unloaded it and the car eventually returned to normal...forgiving me so-to-say. I would agree that complexity is the enemy of reliability. The pop-out door handles on the S often fail, and I'd swap for Model 3 mechanical handles any day. I am not totally sure that 6cm of ride height adjustability in the air shocks is truly worth the added cost or risk of failure.
Another potential drawback beyond the complexity is the additional weight and power draw of the compressor system
I drove my 2012 Model S air suspension until 100,000 and sold it off in excellent condition with no maintenance on the air suspension at all.
I am still driving 2017 Model X air suspension for 50,000 miles and it has been trouble-free.
It's a random sample of 2 cars so it might be statically insignificant.
I've been driving Model 3 without air suspension and other Model S's without air suspension before but I still prefer air suspension. It's more comfortable and less noisy.
So far, zero for my 2 Tesla with air suspension.
Many people may not feel any difference between coil or air. It's up to you.
Four more expensive things to break and repair. Go simple.