In article ,
Simon Langford wrote:

So what difference does steel vs. cast iron actually make?

I read a (US) book on woodburners a few years ago.

They were of the opinion that cast iron was best,
because what they called 'boiler plate' stoves
had a tendency to distort if overheated.

Our is cast iron, a Spencer Sherwood. A big ugly
brute, but it will take huge logs and well sealed,
so that an overnight tickover is no problem.

These are the things I would look at first as well.
Is it a big firebox that will take nice long logs.
Are all doors well-fitting, with sealing gaskets.
Is the ash pan large enough to go days without emptying.
Is it practical to do at least some makeshift cooking
on the top if there is a total power cut (that lasts a
few days).

--
Tony Williams.