One of the major reasons to stay at an onsen was to enjoy the services and half-board Japanese meals, but the kaiseki at the hotel was not very good at all, it does have enough in quality but the quality was lacking, especially the tempura, it was the worst we have ever had. The dinner could only be called a Japanese meal, but not a Kaiseki - so overall it was overpriced.
Re services, it was more like a hotel than a traditional onsen, so besides check-in/ check-out, there was no services at all. No one to show us to our room as most Onsen would have. A server was assigned to give us our dinner, but again, it was like a normal restaurant service rather than like a kaiseki, that the server will explain every dish (wether or not you understand Japanese or not). And the whole dinner experience was very rushed, next dish often arrived before we have finished the last one. Breakfast was semi-buffet and we had to wait for 15min for a table because the hotel was very full.
Overall, will not recommend it. Either book somewhere nicer or just don't bother with staying at an onsen.