Visited January 2019. A major storm system moved in, we had about 1.5m of fresh powder in 2 days. Words do not do justice to the the amazing slack country available direct from the lifts.
Arai is a little low, so it can get wet at the base. But the good riding is all from the top, above a normal freeze line. I did not get into the back country due to avalanche risk.
Lotte Arai is expensive compared to Nozawa, Akakura, Madarao, Tangram etc. At 7000Yen a day including a returnable deposit, there is a big difference to the other local resorts. Facilities are amazing. There is only 1 hotel: Lotte Arai, with around 350 rooms, so the mountain gets a max of 1000 people on it. That may sound a lot but facilities cope very well. There is no easily accessible town (a shuttle bus to Arai Town) so you are stuck in the resort.
Myoko Snow Sports run a ski school there. So there are English speaking instructors.
There are good facilities for children and the hotel offers daycare.
Summary: expensive but good.
Hit this joint in January 2018 when it was 1 month old. As expected, all the infrastructure was brand spanking. Resort and on-mountain eating are very upmarket. Our one day there was sent from the heavens: deep, deep powder and bluebird for most of the day. Words cannot do the day justice; probably the best single day's skiing of my life and I've been skiing since 1969!! Wow!! Just wow!!
Unfortunately this resort has closed as at 10 July 2006. Hopefully will open under new ownership.
All great resorts in this area anyway - see www.klarbooks.com/guides/myoko