Both my mum and sister have heat pumps at their farms, and so far so good, but for both, when they reached the 8 year mark, they had to have some expensive repairs done to things that rusted out. It's not home handyman work. Heat pumps have their heat blown by electricity as well as the pumps for their infloor heating, so you need to weigh costs on what electricity would cost today versus 10 yrs from now. Contrary to belief, they don't self pump.
A new hot trend here now for heat are the outdoor furnaces. You literally have a small 'cabin' that's very insulated sitting outside at a safe distance (insurance companies love them), and you go outside as needed (perhaps once a day or few days depending on outside temps) to feed it. Insulated pipes run underground and into the house with the heat, and it will also do water if you want. A friend has one but she also heats her small commercial greenhouses, hot-tub that runs year round as well as the house, and I think she goes through about 33 bush (full) cords of wood a year. That's a lot of money when you have to have wood brought in. But for just a house it would be far less, again, depending on house size.
Here's more info:
http://www.alternative-heating.com/outdoor-wood-furnace.html