In cold climates…..

[Dodgeman]

Building on a slab promotes the conduction of heat out the edges of the slab, and the floor around the edges can feel cold in the winter. Than is, unless it has been insulated around the perimiter.
The lack of storage space is another negative. Access to plumbing, wiring is more difficult.
But, if you really like the house, why not? As Steve stated, a LOT of houses in this country are built on a slab.
Good Luck!
Dodgeman