It depends on conditions aswell.
15 degrees, cold water, clouds, windy.. take the drysuit.
but 15 degrees, water between 15 and 20 degrees, sunny .. I’ll take my shortarm wettie
Between 10 and 15 I’m in my Pyro, so comfy.
When it is not really cold I’ll just put on my drysuit underlayers at the parking near the water so I have dry clothes on my way back home instead of swetty and smelling underlayer..
The best thing to do is layer up adequately. If it’s a bit warmer you could use the dry suit and use thin ski underwear (to let the sweat though) and thin fleece, to hold the condense and sweat. Where I ride, the water warms up quickly, and with water above 12°C and air around 15 I personally don’t like the dry suit anymore.
My suits: OR Pyro Lite, 3mm “long john” wet suit (bare shoulders) and 3mm shorty, plus a collection of 1mm neoprene long and short sleeve shirts. So no 5/3 or thicker winter neoprene anymore.