I have a wayang rogue: 5 that's about to take levels in sleepless detective. This PrC is great for a rogue with a high int. score due to its ability to add int. to perception. My rogue also took traits that made spell craft a class skill and allow him to use int. for UMD, makes the sleepless detective's ability to detect magic at will means you will be able to identify and use almost any magical item which is handy for a party when you're lacking a caster. I'm just taking 4 levels and then going back to rogue so my sneak attack dice will be the same as someone who just went pure rogue, thee class abilities after 4 aren't that usefull in my opinion. Feat wise with a high INT. I'd reccomend something that boosts your skills, specifically knowledge checks, but other than that take whatever feats you like. In combat just keep using your detective like a pure rogue and you'll become a great asset to a party.