Yeap, go for power first. You need other support ninjas to carry him (e.g. Danzo). I rushed to get him early, but I couldn't really use him effectively until I raised my BP and initiative significantly higher. I saved up to get him over a couple of events, and spent a minimal amount of ingots (100-200?) at the end to finish getting him. However, once you have him, it's great fun to run him with other ninjas like Bee/Roshi, etc.