Sharing my thoughts after two nights here. Booked two rooms with river views for our group of five. Diamond benefits didn't extend to the second room, but they offered a "Diamond" discount (around 10%, can't remember the exact number) on a Breakfast + Executive Lounge package for the other three guests.

Used the app for online check-in and no upgrades given (not sure if that affects their proactive upgrading). After asking at the desk, they moved the main room to a castle view on the same floor. Rooms weren't ready until 3PM though. Check-in staff were pleasant and chatty.

Rooms were pretty good overall. One room was missing a Nespresso machine, and when we asked about it, front desk said none were available. No bottled water in rooms. Instead, you need to collect water with a hotel-provided jug from a separate room near the elevators.

Breakfast was very mid and packed. Mostly guests from India and China. Poor egg station chef got absolutely grilled by guests with some pretty demanding omelette orders. Didn't go to the Executive Lounge myself (let two from the other room use my access instead). Heard the cocktail service was excellent.

Views from both the breakfast area and lounge are really good but will book something closer to Namba or Umeda next time (Myself and missus have been to Osaka numerous times fwiw)