I don't know about the best, but I have 3 "scrounged" heat pump dryers and they are quite different.

The first one is a real cheapy - a Solt from the Good Guys. I salvaged it brand new but damaged from the skip behind a store, they had dropped something heavy on it (probably off a forklift) and dented the top/side above the water collecting drawer, and thrown it out. I did some basic panel beating to straighten the top of the side panel, and all is well. No plastic was broken.

This is a fantastic dryer, works just as well as any Aussie 240V 10 amp vented dryer. I am really impressed with it. If I had paid for an undamaged one, price was under $900. Filters are well designed and easy to access.

The second is an LG with the self-cleaning condenser. I'm not sure why this was discarded, but I salvaged it and have never found anything wrong with it. The first time I used it, a blob of lint appeared in the water collection drawer, it might have had a lint blockage in the water tube that was dislodged by being thrown out, lifted into my car and carried home??? It also works really well, I do wonder about the self-cleaning condenser though, there is no easy access to it if it ever gets clogged. I gave it to my sister as she has a matching LG washer, she is very happy with it.

The third one I salvaged is badged a Hisense, which was made by Gorenje. It has a less powerful heat pump system, only uses 400 watts and is quite slow. It is officially rated at 800W but I have never seen it go above about 450W. Early on I thought is might have a fault in the heat pump (loss of refrigerant??) but now I believe it is normal, for example the towels cycle when you select it shows 3 hrs 15 min on the display, and it dries in less than that so I think it is not faulty, just a bit slow. It still does the job just fine, but I can understand someone replacing if if they were sick of it being so slow. The LG towels cycle display starts at 2 hours, and it is indeed much faster. The Hisense also has a clumsy filter built into the door, I don't like the design much. I still use it occasionally just to test it out, but I rarely ever use a dryer, I have a clothesline outdoors and more clotheslines in the greenhouse for use in wet/cold weather, so I don't really need a dryer at all.

I do have another heat pump dryer that I scrounged, but it isn't working - the heat pump works fine, but the motor won't drive the fan or drum - that is an Ariston, made by Whirlpool, it has a tiny flat pancake motor driven by an electronic controller, either the motor or controller has failed.

There was a Bosch heat pump dryer in a skip behind a store I looked at recently, the door catch had failed and some idiot had drilled the door and side panel to fit a webbing strap with click-buckle to hold the door shut, a rough and ugly repair that made me decide to leave it behind. It was also dirty and knocked around.

I take these items from the skip with permission from the store, just to be clear.