I've always looked at it from the idea that if you have water issues now - fluctuating volume or temperature issues with one fixture when another fixture is flushed or a washing machine kicks on - then while a thermostatic valve may be best, a pressure balancing will suffice. However, if going with multiple outlets in a shower, then thermostatic valves may be the better option.

However, for new construction that is properly planned and plumbed, or in an existing house where water problems don't exist, then two pressure balancing valves will usually work just fine.

In my own master shower I have the same set up, an overhead rain and a bar mounted hand. They both get used simultaneously and there has never been an issue with flow, even with laundry, toilets, the dishwasher, and the kids doing their thing in there bathroom all at the same time.

Mongo

Mongo,
This is new construction. Do you have the pressure valves?
Thanks for your input.

Yup. Pressure balanced.

Mongo