I had 13 years as a bedside ICU RN, this was across all adult specialties including years of travel nursing as well as brief stents in the peri-op and home health fields. I've been a critical care NP for 6 yrs now and its been a pretty good transition for myself as well. I originally was thinking about a residency/fellowship but I was fortunate to find a job where I could OJT in a supportive environment. I do think a residency is good as you can never go wrong being more prepared. In my experience and in helping train new grad hires it really depends on your learning style, as far as are you extremely self motivated and going to seek out the information aggressively or do you need more direction and structure for learning guidance?