There are both 110 and 220 volt receptacles in every cabin. You'll find one 110 volt outlet on the hair dryer in the bathroom, and both voltage outlets at the desk in your cabin. If you're bringing many electrical and electronic devices, I highly suggest bringing a power strip so you can plug more than one device in at a time.
The Spirit has the most beautiful decor of all the ships in the NCL fleet, in my opinion. It's Asian decor, artworks, and carpets are very unique for North American based cruise ships. I've read somewhere that the round carpet in the main atrium cost $4 million. It has far more teak decks than other new built for freestyle NCL ships.
As you should have gathered by now, I really like the Spirit. But it does have a few short comings. There are no mini suites, nor many cabins that can accommodate four passengers. There are no refrigerators in standard cabins, you'll find them only in suites. But they will refill the ice in the ice bucket twice a day. There's no self service laundries aboard, just a ship's laundry. There isn't much room by the amidship swimming pool topside for sunning, but there's plenty of room by the aft pool, as well as plenty of shade.
Every ship has compromises in its design. Remember it was designed with built in compromises for the Asian market when you are aboard, and that it has been modified for the North American market. I believe the changes made to it to be able to sail from North America have been successful.