Basically with a Euro transom, say for a 23' model, you'll get less room of the previous 21' model of that same boat ... but at the price level of a 23' boat. Or simply put, less room - more cost. Less room overall if one counts the 'new integrated pulpit' into the length too.
Seriously, not that GW does this as blatently, but there used to be a website that showed the old 20' Pro-Like CC, where it progressed to be their new 22' CC model with the Euro-transom, which then became the next year's 23' model with integrated pulpit. Ahhhhh, it had less cockpit space than the old 20' CC model with cut-out transom. But note, every foot greated you go in hull length adds $1,000s to the baseline price.
Sometimes though, you will get an increase in beam to the hull under the new configuration.
Others can opine differently, but all I know is that my 25' Parker is 25' from stem to stern, adding 3-4' for the OBs off the engine bracket and another 3' for the pulpit, and my 25' hull measures almost 32' overall ...