I would have a pellet fire over a heat pump any day.
We have a 5kw heat-pump and my 1.5kw scope wall heater does a better job of keeping us warm. ( we have had the installer back several times and he says it is withing spec )
Unfortunately we don't have the room for one otherwise I would have installed on years ago, the chimney on a pellet fire can go through a wall, they are very efficient and if I recall they pipe is plastic as it just does not get hot, just lets out a little smoke.
Ultimately I would have a wood burner with a wetback but just don't have the space to put it in our lounge.
Sounds like there is a problem with it or not the best brand, as that hasn't been my experience with heat pumps. They do also have the benefit of cooling in the summer. They are also fairly responsive, and economical compared to a regular heater.
Wetbacks are supposedly not a great option these days with the new fires, unless you have the water heater right next to the fire, there is usually too much heat loss through the pipe across the distance. Also it make the fire less efficient.