Hi Bob! I missed the stats for Maytag's new TOL. Thanks for providing that info.
I take any db rating with a grain of salt. Remember when some top-loaders claiming "18-lb. capacity" would be doing well to hold 14-15 lbs. in the real world?
My former dishwasher, an LG, was rated at 45, but the average when read 24 inches in front of the machine with a decibel meter would be 47-48 db. It was actually noisiest while draining. The Maytag that preceded it went well into the 50s, and the main wash showed a bump/peak when the detergent dispenser lid would pop open.
The GE PDT750 is much quieter overall, especially when filling and draining---two points in a cycle when db's tend to be higher and, as Rick pointed out, the sound quality is more annoying or at least noticeable. Machines also drain and fill several times, so it's a repeated issue during the cycle.
Personally, I want a dishwasher to be as silent as possible. I trust it's doing its job. I spend hours in the kitchen with the machine running one load after another, so I love the super-quiet GE.
Alternate rack washing: I have no problem with the concept, and the three dishwashers I've had that use that system (Frigidaire, LG, and GE) all cleaned well. Plus, I tend to use the top/bottom rack only option frequently; others may not.