Love it, love it love it, we've had our stove for six weeks now, no problems to report except a cracked rear fire brick that our installers replaced without quibble.
Have been burning hardwood logs and smokeless coal and a mixture of the two, it will stay in all night with a small shovel full of coal and the vents shut down , open the vents in the morning put a log or two on and away we go again.
It's very easy to light with a fire lighter and dry kindling in ten minutes it is putting out an impressive amount of heat and is very control able with practical sliding vents that give an all most instant reaction to the fire.
The maximum log size is an useful 16 inches.
Based on our experience of the stove so far I would recommend the x50 to any one.