Which factors in PostDoc opportunities choice? Many of you probably have already lived these career turning point: your PhD program is going to end, and you have to choose an university research group to apply for a postdoc position. 

Which factors do you consider as more important in this choice?

Take research group X at university Y.
Which factors you consider to decide if it's worth to write to them for a postdoc opportunity?


Research group project's affinity with your PhD research work?
Research group's excellence, and international ranking of its team
leader researchers?
Research group members' human affinity with your personality (if perceptible)?
Research group project's scientific novelty and genius?
University excellence, and its international
ranking? 
Distance from your hometown? Proximity to your hometown?
Salary?
Going abroad?
The university city/country way of life?
Other elements?


Please tell which of these (and other) elements you consider the most important (or by giving a percentage to each, if you want).

Many thanks! :-)
Actually, I think the frame of this question isn't quite right. I would argue that these are criteria that I would use if I were choosing between multiple postdoc offers, but these are not necessarily appropriate when deciding where to apply.

What I would do is decide what my "deal-breakers" are: that is, what are the criteria that would prevent me from accepting an offer, regardless of how good it is? For instance, if you need to take care of an ill family member that lives in a specific location, then you're probably not going to want to consider international programs. Similarly, if you're determined to go into industry, you're not going to be inclined to take a purely theoretical postdoc project.

However, once you've decided upon those deal-breakers, if you then see a project for which those criteria do not apply, then you should go ahead and submit an application. You don't have much to lose by doing so.

Once you have the offers, the challenge is tougher. All of the criteria you've listed are valid, and it's hard to say which of those might be the most important—it all depends on your own personal circumstances. One hopes that research concerns are the most important of all, but as I've mentioned above, there are valid reasons why that might not be the case. The only thing that I would make sure of is that whatever option you decide for in the end, it helps you in moving on with your career beyond your postdoc. There's nothing worse than getting stuck in "PD purgatory," where you can't really stay as a postdoc any longer, but are having problems moving to a permanent position afterward.