What is the best type of oil fired boiler (hydronic) to buy?

I would recommend Biasi brand. The system itself should cost that much money, but perhaps it would be close to that with labor/instalation costs. We have had a Biasi for years and never ran into any problems at all. The source link below is to a Biasi B-10 Oil Boiler, which runs $1,550.00. The technical info and specs are available at the source link below. Hope this helps and best of luck finding the best one for your needs!