What accuracy will I get?
Is like asking how fast your car will go; it all depends on your type of car, the road, the driver and so on. The same goes for RTK networks and achieving accuracy, it depends on the visible satellites, the distance to the network, your equipment and all.
In general, with the UNI-GR1 and normal conditions, you should be able to achieve an accuracy between 1-3 CM easily.