Characteristics of cherry rootstock - size of tree, disease resistance, soil compatibility (handle clay based soils, water logged soil), cold hardiness, time to bear fruit, etc.
I would think Mahaleb rootstock would be a good choice for your area - it supposed to be cold hardy. If I remember correctly it produces a relatively large tree, 80% of a full size tree. Mahaleb does not do well in clay based soil with poor drainage - therefore it was a poor choice for me.
This site has a good description of cherry rootstock. Usually your smaller dwarfing trees set fruit earlier.