A lot more expensive, Mally, but they do look great.
As Slack said, their advertised heat output is important.
You would need to look up the heat output of each existing rad and replace with the same.
Heat output is given in either BTUs (British Thermal Units), or simply in Watts.
Figuring out the heat output for modern horizontal rads is easy... just look in Screwfix for instance. Bear in mind that rads can be standard, or high-output models.
Also single panel and double panel.
Assessing outputs for older chunky rads can be down to a little educated guesswork.