I just did the program last year..........
The majority of people def. do NOT get a 1st author paper. I would say about 25% or less. Id say those with their name as 2nd or lower authorship is probably around 40%. Multiple papers is quite unheard of.
I would say that alot of students appear to do the program with a significant amount of their reasoning being residency. But, to each his own, this will happen with any med school related fellowship/award, etc. Id say most have a great time in the year, not just in the lab, but making friends, exploring nightlife, etc.
Of course there are those that leave a bad impression on thier labs. Id say this has nothing to do with the program itself. If there are investigators at NIH that look down or do not take HHMI students because of this, they are not good mentors and its probably a favor they are not taking people.
Do people match well? of course, above average, of course. Is this mostly because of the program, I think not. I think the type of student who applies to such a program is probably already driven and intellegent, and most have impressive resumes even without HHMI. So I think this is more of a reflection of the type of student that does the program, rather than as a result of the program itself.
Does HHMI make us feel like we are the cream of the crop, etc. Yes, they try. But most of us were intellegent enough to realize that this is not really true and that labs were not begging us to join.
In sum, I would not recommend doing the program if you know you are not interested in research, or you will be miserable. Dont feel guilty if you are considering it in part because of residency, most of us put this into consideration. Be realistic. You really cant do much in a year. In reality, it ends up being more like 8 months including when you arrive, depart, vacations, etc.
good luck, feel free to ask questions in this forum if you like and I can try to answer them.