Smaller companies have pros and cons. The good is that your contribution to the company is more likely to be noticed. It can also be good if the company is growing because there may be a lot of opportunity to move up with that growth. The bad is that sometimes the benefits suck.
I'm not too worried about the benefits really. We have health/dental through my wife's employer because it's cheaper and significantly better. I'm young enough where term life wouldn't cost much more than my optional life insurance. The TSP & pension are indeed excellent, but at least for the TSP, there certainly are alternatives (Vanguard IRAs, not quite as "cheap," but nothing is).
Would be more of a problem if my wife didn't have such excellent health/dental coverage at her job, but I foresee her staying within the company for a long time, as she really likes it -- even outside of the new job "honeymoon" period.