You'll have to expand on that matjerarj...
I only have experience of the Kedco boiler but If a small hopper or bulk storage are set up correctly then there should be no major issues. A small hopper and auger should be cleaned every 3/4 months as a certain amount of dust will fall to the bottom, the better quality the pellet the less dust but there will always be a certain content of dust in the pellets. A bulk storage silo (canvas type on a steel frame) should also be cleaned out every 6 months and this again is a simple procedure. Self build pellet stores are a different story and these should be fitted with a grate type fitting in the bottom corner of the pellet so that any dust will fall through to an area below the bottom which can be cleaned easily.
As for a buffer tank, well if your running UFH then its a recomendation for efficient uses of pellets. If you have Rads then its not essential, different suppliers will recommend different set ups. Talk to your supplier.
BTW, Gerkros seem to be overspecking the size of boilers needed. 40KW is a massive boiler for a 2600 sq foot house. 30 Kw would be plenty, I have a 24kw Kedco in my own house which is 2400 sq foot and its plenty.
Look, Wood Pellet Boilers are not as hands off as oil, its new technology, people need to plan ahead to implement the solution properly. If this is done, if all installations are carried out to the required standards and if the boilers are commissioned properly then should have a proper working solution. You are also of course at the mercy of the quality/supply of pellets. I got a guarenteed supply of pellets with my boiler.