Japanese efficiency and really decent cost! Flew RT Narita-Sapporo Sept 2014 and loved it. English website that was understandable. Every employee super nice and since I was the only non-Japanese on the flight, did all the announcements in English as well as Japanese. No Frills and they mean it.
Estimate your luggage well: As cheap airlines are trying to minimize their costs they usually have a restrictive luggage policy. - You can board the plane with only one piece of hand luggage (usually not heavier than 10kg and with maximum dimensions of 55x40x20cm). For detailed information on hand luggage allowance check the website of the carrier. - If you plan to also take hold baggage with you, you will need to pay for it online (when you book your ticket) or at the airport. Keep in mind that it is cheaper to pay for your checked-in luggage online than at the airport.