Material conditions and outside factors are the easiest part of a postdoc to identify, so I'll do those first, even though they are the least professionally-relevant.
- Money: four of the postdocs pay x (a funding agency's standardized salary, which can be supplemented in a very limited way; one postdoc said that in effect he made 1.15x with supplementation; based on my current salary, I could argue for 1.4x, but I doubt I would get more than that 1.15x). One postdoc pays 1.3x. Currently I make .8x, but that's working half-time so that I can spend the other half on my own work, so if I worked full time, I would make 1.6x. My current city (where I would make 1.6x full time) is equally expensive as two of the 5 cities (where I would make x), and much less expensive than the other 3 cities (where I would make x or 1.3x.)
- Benefits: I only asked one of the postdocs, and it makes available the university's standard employee insurance plan. As I discovered last year, some postdocs are not considered employees so have to purchase insurance on their own and then be reimbursed: while this insurance does not seem to cost the postdoc anything, this is risky because it means that your health information is tracked by companies which work like credit bureaus, and that frankly scares the bejeezus out of me. If you broke your ankle while skiing as a postdoc and for some reason needed to get insurance on the individual/non-employee market 20 years later, your rates might be extremely high just because you broke your ankle 20 years earlier. I'm not exaggerating. It's a complete deal-breaker for me not to be considered an employee for health insurance.
- Office space: One postdoc is in a space-constrained school, but would nonetheless give me my own small office with a small window. Another postdoc seems to put its postdocs 4 or 5 to a windowless office the size of my current one (except my current office has a window,) but they claimed that the exact office situation was negotiable. I can picture sharing an office with one person, perhaps, but I just don't see how I could happily share an office with so many people; I'm shy and just not used to not having a door that I can close and a window to look out of. Three of the postdocs did not give me a sense for what my office situation would be: I suspect that one would be a windowless cubicle and two could be decent offices, though I don't know.
- Material support: A few postdocs buy new computers for the fellows, and even give a choice. A couple seem to give the postdocs 5 year old computers or whatever happens to be lying around. Some postdocs seem to make travel funds available to compete for. Others give nothing. Others fund any travel to promote the PI's project.
- Safety: Two of the postdocs are in very sketchy areas, where people actually said explicitly it is not safe to walk around, especially not at night. Two are in slightly sketchy neighborhoods, but generally safe. One postdoc is in a really nice neighborhood. My current postdoc is in a sketchy neighborhood, intermediate between "very" and "slightly" sketchy.
- Weather. One postdoc has nice weather, two decent, and two awful.
- Personal life: I have friends in all of the cities, thankfully. I can easily see myself living in the cities for four of the five postdocs. The fifth would be cool, but doesn't feel remotely like home, perhaps because it's a different region of the country than I'm used to; also, my friends in this city (both male and female) have had trouble dating, ironically, since given that they're both males and females having trouble, I would think they could find each other. Three postdocs are in cities at least as interesting as my current one; two are in less interesting cities, but close to better cities.
Okay, that's probably really boring for anyone other than me. And even for me. I'll try for better. I have an interesting interview story to write up in which my interviewer was extremely frank.