We bought this Wiseway a couple years ago; this is our second winter season. We wanted something that didn't require cord wood or electricity.
I'd buy another one if I had somewhere to put it.
We don't have the ideal installation, since we just plugged into our existing chimney, but it worked the first season while we learned about all the ins-and-outs.
Now that we've finally got everything situated (Vacu-Stak chimney cap, pine pellets, three inch vent pipe, fresh air intake), operation is fantastic.
We have the smaller BTU model (which I think is all they sell now), and it's been heating our house fine from where it is located. We do have an oil-fired boiler as well, so there's backup.
If you're able to do the optimal install (15ft vertical 3-inch pipe), you'd probably have no problems right out of the box.
Well...