I have grown it a few times, though not this particular year owing to a fall curtailing my gardening ambitions
It ok, and is nice if you want to have something different, but it is not my favorite veg. Its a little like a very mild parsnip, but much smaller and more fiddly to prepare. I would only grow a couple or three short rows (4ft) But it has not been difficult in the past. Though this year most things outside in my area have done badly.
I would probably grown Salsify in preference to Scorzonera, there is a bit more to eat on it and they taste pretty similar.