I had to attend a convention at the Osaka International Convention Center and this hotel was in a great location: 15 minutes walking distance. There's a 7/11 just next to it so you can buy anything you need without having to walk a lot.
The nearest subway station is Honmachi, on the Yotsubashi Line, but it also connects to the Chuo Line and the Midosuji Line, although for the last one you'll have to walk around 15-20 minutes. However, once on the train you're only a couple stations from Umeda or Namba.
The staff was nice, but they didn't allow me to check-in 45 minutes in advance. I had to pay extra if I wanted to do so, so I just left my baggage. No big issue, though. All members of the staff were very friendly and helpful, and they can communicate in different languages too.
They have free breakfast which was a pleasant suprise. However, the dining room is a bit small so you'll have to share a table with someone else unless you're part of a group.
The room was clean and comfortable. WiFi signal is very good. I could connect to internet with no issues.
Overall, a nice hotel. Would definitely stay again if given the chance.