Building large scale Quantum Computing will be a huge hassle to as they have to get designed, verified and then finally built.
Since, it is difficult to build and program, they are crippled by errors in the form of noise, faults and loss of quantum coherence, which is crucial to their operation.
These errors then destroy the exotic quantum properties of the computer. Making Computing harder.
Quantum Computers have to be stored at a very low temperature, 0.015 kelvin. And they should be isolated from heat and vibration.