I'm going to be planting a garden of perennial things like raspberries,
blueberries, strawberries, rhubard, asparagus, etc. in central Maine.
I'm considering whether to use raised beds edged with granite or just
plant in the ground.

Are there big advantages to be had planting these materials in raised
beds? It's more trouble and expense to install initially and a bit of a
hassle to cultivate, since I already own a tiller for use behind my
garden tractor, but if the long-term advantages still outweigh the
disadvantages, I'm willing to to go for it.

Any suggestions?