This is such an open-ended question. Just like in a house, before you arbitrarily replace the thing with the same size, you need to do some analysis as to what the right size is. Now, it's possible it was the right size, but that seems to be by far the rarity. It may be that the place could be well served with a much smaller boiler, with a smaller upfront cost and on-going fuel costs, along with being more comfortable. But, without knowing more about the building, it's radiation types, zones, insulation, design-day temperatures, insulation levels, windows, etc., there's no way to say. Then, throw in most (by no means all) people on this forum are from the USA, and not all products available here are available there, it makes it tougher.
But, first thing, before just replacing with the same sized equipment, pay someone to analyze your actual needs and start saving some money.