Renovated Condo but 1930s Fuse Box - buy or run?

[Felicia Kurniawati]

I've been looking to buy and have an accepted offer on a pre war condo unit in Jersey City. The place has been beautifully renovated by the current owner (downlights, new modern appliances, upscale bathrooms). However home inspection revealed that the fuse box has not been updated since the 30s, and the fuses are overrated. The building is well maintained but I think it wasn't all updated with the latest wires so getting more electricity lines to the unit would be prohibitive. The outlets in the bathrooms are gfci. However the rest are open ground which a licensed electrician said suggests that they may still be running on old wires and that there may still be knibs and tubes. Permits were obtained by the owner for the renovation and the city signed off on it, but as it is an old building, my understanding is that older setup would still be accepted as they are grandfathered. 

Is this "not a big deal" and part of living in a pre war building, or would most buyers stay the hell away from it?  Will insurance be more expensive than normal? How would you deal with the situation?