I have a buddy that went from forced air to boiler, I just had forced air.

he overall likes his boiler better, he has his setup to heat hot water, so unlimited hot water in the winter without installing a on-demand boiler.

Dislikes are other than the high initial cost, is that somebody has got to be around to feed the boiler to keep the fire going. With a forced air furnace if the fire goes out, meh, not such a big deal, fire goes out in the boiler it’s a big deal.  
Most boilers will take pretty big chunks of wood which is a advantage in the wood splitting/cutting department, but a disadvantage in the wife loading the boiler department.