Flew them on our way to a ski vacation and I thought they were great. Very efficient and on time. Reminds me of Southwest Airlines in the US.

What an amazing experience!
Great price, easy self check-in
Staff are friendly and helpful.
Prompt takeoff, comfortable flight.
I would absolutely use this airline again!

It was my first flight with Skymark for a last minute booking, and a very pleasant surprise, especially with the never ending issues Boeing 737 seem to be facing. The seats on this 737-800 were comfortable Recaros, We took off a few minutes late but were out of the plane 15 minutes early. Friendly service. I will fly Skymark again, assuming my return flight is similar.

Perfect service, especially for traveller with road bike.
Polite, fast ,trouble free and the custom kitkat and coffee is super nice bonus.
Switching from ANA for these guys
I do wish they had on board wifi, even at cost

主に大都市・各地域の主要都市を結ぶ航空会社として、高い人気を誇ります。輸送の頻度や量が多い路線に絞っているからこそ、搭乗直前でもANAやJALよりも比較的安価でチケットを購入できます。便数や機内サービスも大手航空会社とほとんど遜色なく、LCCに見られるような追加料金を要するオプションも少なく、少なくとも都市間移動の交通手段として利用する上では最適な航空会社と言えます。
個人的な感覚ではありますが、海外からの観光客の利用が最も少ない路線という印象があります。大手のANAやJAL、もしくは移動手段にお金をかけたくないためにLCCを使う、という二極化があるのか、あるいは航空連合に加入しておらずポイントの還元が出来ないからかもしれません。勿論、海外の観光客が使いにくいと思えるようなサービスの質は見当たりませんでした。

注意したいのが、事前予約した際に発行されたQRコードが自動チェックイン用ではないことです。必ず保安検査前のカウンターで正式なチケットを発行してもらい、そのチケットを利用してチェックインする必要があります。キャビンアテンダントの接客対応については、臨機応変さは大手航空会社と比較するとやや劣っている、という印象です（それだけしっかりと教育・訓練されているという証左かもしれませんが）。
座席の広さ・前後のゆとりはほぼ全席同じで、上位クラスの席は非常に少ないか皆無です。機材によっては座席に充電用コンセントは配置されています。

This airline are highly popular mainly because it connect to major cities and regions. Since it focuses on major city airports rather than regional airports, you can buy boarding tickets at a lower price than with ANA or JAL. This is true even just before the boarding date and time. Not only do they have as many flights as the major airlines, but they also charge less in additional fees due to options like the LCCs. As far as inter-city transportation goes, it's a very just airline.
My personal feeling is that there aren't many international users. I think it's either a polarization of users to use the major airlines or LCCs, or it's a lack of membership in the airline coalition that prevents them from redeeming their points. Of course, I didn't find the quality of service to be difficult for foreign tourists to use.
The most important thing to note is that the QR code issued to you when you pre-booked is NOT for automatic check-in. Skymark always requires you to ask for a ticket at the counter. The cabin attendants seemed to be a little less flexible in their approach to customer service. Of course, that's not a bad thing at all. Seat size and spacing between the front and back of the seats are nearly identical in all cabins, with very few or no seats in the upper classes. Depending on the aircraft, charging outlets are located in the seats.