I'd at least take a gander at a fully condensing, modulating, wall boiler. It would save a ton of space and efficiencies are well over 90%. I put one in my garage for the hydronic system and it's been a good solution.
I'm a DIYer though...so it if needs an igniter or a zone pump or what not, I do that myself. I agree with the above...if you aren't going to be fixing it yourself, you need to buy something that someone local can work on if needed.
Does your boiler do double duty and also supply your domestic hot water? Also, where are you? What fuel does it run on? How much $ are you spending a year?
Any of those items could change my answer.
Phil