Slippery
Any flooring can be dangerous if something is spilled, because the floor becomes slippery. Rubber flooring is the worst though, because it is even more slippery than other surfaces. Spills need to be cleaned up immediately, and even after the spill has been cleaned up, there should be a towel over the spot or everybody in the house should be informed of a slippery spot until the floor is completely dry.
Maintenance
Rubber flooring is very difficult to maintain. Dirt builds up quicker on rubber than on most surfaces. Rubber flooring needs to be swept, mopped and vacuumed a couple of times a week to keep it nice and clean.
Cleaning Products
One of the difficulties of rubber flooring is that it needs to be cleaned often, and there are certain cleaning products that should not be used. Turpentine and acetone can both do damage to rubber flooring, so do not use cleaning products that contain either. Rubber floors will also be damaged by acidic solvents, so do not use cleaning products with acidic solvents. Even colored cleaning pads can be harmful to rubber flooring, because they could stain the floor.
Scratches
Another disadvantage of rubber flooring is that it is one of the easiest surfaces to scratch. Dropping a knife or dish that breaks could scratch the floor. Pets that decide to claw at the floor can scratch rubber flooring. Even using a rough material to clean with, such as steel wool, can scratch a rubber flooring.
Price
The price of rubber flooring itself has advantages and disadvantages. If rubber flooring is properly taken care of, then the advantage is that rubber flooring will last a long time and the investment will be worth it. The negative, though, is that the initial cost of rubber flooring is going to be pretty expensive.