Pros
Labs are essentially not beholden to any sort of grant funding. This is awesome for many reasons: (1) as a postdoc your salary isn’t tied to a specific grant, meaning you have a lot of freedom to define what you want to work on; (2) high-risk, high-reward science is encouraged; (3) PIs (and other people) are less stressed out; (4) in general people are super collaborative bc no one’s worried about where the money will come from. NIH is huge, meaning you can find someone who is an expert on just about any topic in all of biomedical research, and they’re probably willing to collaborate with you (see previous point). Plus it attracts great speakers, seminars, conferences, etc. The resources are generally awesome, and the NIH Clinical Center is the world’s largest research-dedicated hospital, meaning every patient that’s admitted comes in under some kind of research protocol. This is pretty cool, bc patients are very open to participating in research (basically by definition), all the necessary research infrastructure is in place, and in addition to the more standard stuff you can also get some really interesting pathology (patients come in from all over the country, and sometimes the world). NIH has a great post-bac program that tends to attract really bright and motivated recent grads.
Cons
Less opportunity to work with and mentor grad students, if that’s something that’s important to you. Labs can feel a bit top-heavy (with mostly postdocs and staff scientists), and then a big gap before post-bacs. Your mentor(s), especially if he or she is more senior and/or has been at NIH a long time, may be less savvy about the academic job market: what search committees look for, what goes into preparing successful job talks, etc.; especially if you are targeting arts & sciences departments (some of them may or may not have a bit better insight into medical school departments). The emphasis on high-risk, high-reward stuff – combined with the relatively high number of NIH “lifers”, i.e., PIs and staff scientists who have been and/or are planning on being at NIH for basically their whole career – means it can sometimes feel like there is less of a sense of urgency to complete projects quickly and publish. This is not an entirely bad thing, but as a postdoc you will generally be on a quicker timeline than many of those around you, so you have to stay on yourself to be publishing/hitting certain milestones/etc. Because this is the federal government after all, certain bureaucratic things (travel, getting purchases approved, etc) can be really annoying and time-consuming. Health benefits for postdocs and other fellows are not the greatest.
