Pros
HHMI is a very prestigious name in the Medical Sciences field. This will no doubt be a boon to building a resume that will help to land that coveted post-graduate job. Compensation is better than average for non-profit research, but is not up to par with the money being made by those who go into the Biotech realm. Benefits were not offered for this postion, but a travel stipend was provided and I was given weekly food allowances. In general, the laboratories were modern and stocked with mostly new equipment. You are given almost an unlimited account for laboratory purchases.
Cons
As is the case with nearly all jobs in the Biomedical world, a Bachelors degree lone will not allow to advance through the ranks at HHMI. While the work atmosphere is generally positive, there are a fair amount of disgruntled employees - especially among the post-docs who were not offered grants and now work as glorified lab techs. In addition, the multi-ethnic nature of the work force can lead to frequent miscommunication and sometimes becomes unbearable. If you can, I would try to find employment in the biotech industry before considering a job at HHMI. In industry you will find that your research efforts are more concentrated than they are at HHMI.