It is probably the most comfortable method of heating. You don't have restrictions on where you can put the furniture. It costs more to install, but usually less for energy. If you want a/c, you can't share the cost with the air ducts already there for heating. If the pipes don't leak (and they shouldn't), they are a closed system that gets heated fairly hot so you shouldn't have anything growing in the water. Shouldn't be a problem. Same idea as radiators...you don't really care.
Electrical heating mats also should last. While you can use them as primary heat, that may only apply in mild areas. They are usually restricted to a maximum of 12W/sq foot - check with the manufacturer. You'd have to see if that would be enough with a heat load analysis. They should last a long time, too. You might have to replace a thermostat along the way, but not the heating mat.