The most important part of using peat based mixes, in my experience, is to not up pot the plant too early otherwise it'll get waterlogged.
Fully agree with that.
A container of pot mix without a plant loses water by drainage and evaporation.
Once planted, the plant pumps out water via transpiration.
As the plant grows bigger, it pumps out more water, so the media will dry out faster than with drainage and evaporation alone.
The way I see it, it is the size of the plant in the correct sized pot that as the issue, as much as the media.
Small plants often don't do well in big pots, as they can't pump out enough water to balance water logging.
This could vary seasonally, they might be ok in a hot period, but go backwards in winter.
