Niseko has a wide range of slopes and facilities (pensions, hotels).
Higashiyama is ok but the slopes of Hirafu aren't well marked but it didn't matter because falling on the black diamonds in 2 feet of powder is practically painless (ie. good for the beginner snowboarder). Some Australian pro boarders claimed "Powder doesnt get any better than this." Even at the end of the day the snow is in great condition. The hills at Hirafu are better for boarding - wider, and more variation, and with more relaxed slope. The mountain is exposed so it can get windy(there is only 1 gondola, so the chairs get chilly) and the weather is very changeable but when clear the view of Niseko is amazing.
There is a half pipe, lots of runs, good retaurants, and unexplored powder. You can get a combo lift ticket for all Niseko resorts which means a lot of runs. There is a good mix of skiers and boarders. We have gone on weekends and weekdays and on weekdays there was virtually no line ups for the lifts, and it wasnt bad on the weekends. There are shuttle buses running from the bases of the 3 resorts. There is a nice community feel in Hirafu (restaurants, bars, pensions), and other winter activities such as snowmobiling and dog sledding.