I remember playing the demo for this ages ago and i enjoyed so I decided to just get it!
I was also playing Hotel Dusk at the time and this really got my "Murder Mystery Juices" flowing! The story is compelling and you genuinely want to know what's going to happen next. It's also interesting to play the game from the two different perspectives of Keats and Ellen, you see the same events, but in totally different ways, and you'll start to develop your own views on characters and goings on in the story.
The battle system, although extrememly repetitive at times, has its little quirks. It reminds me alot of...well...Pokemon. You know, walking around bumping into all sorts of crazy critters and capturing them, and then doing the usual leveling up process. And the boss battles remind me of the Zelda bosses, where you have to come up with a certain strategy to take them down. All in all, its a good RPG for your PS3 collection.