My workshop is the stable end of an old coach house, approx. 15' x 15', built of stone and brick, with a lot of heat loss into a loft above. I put in a concrete floor so it's pretty cold in there. (The other end is a double garage with access from the workshop so one day, hopefully, that will become an extension of the workshp - she doesn't know that yet!)
Set up initially for woodturning I realised that I would have plenty of shavings to dispose of. I also, fortunately, have an unmlimited supply of logs so the heating answer for me seemed to be a woodburner.
I installed a Hotspot Relax R.3 which has proved to be excellent although I used stainless steel flue pipe rather than the Hotspot galvanised stuff which seemed a bit flimsy.
It certainly does the job, although obviously it does take up a fair bit of space, is easy to light and control, and gets rid of all the workshop rubbish. It wouldn't survive on that alone though - I do use a fair few logs.
FWIW. Trev.