Does one always accept good funding (Marie Curie)?

Question

I have recently started a postdoc in a prestigious US university, making a leap between scientific areas. Right before starting it I have applied for a rather competitive European fellowship (Marie Curie Individual Fellowship), also in this new scientific area.

Today (5 months after the application) I learned that I got the fellowship. I have not actually expected it and I was applying more to get experience in writing grants, to apply seriously a year or two later (since in general I would like to end up in Europe in the long run). I honestly do not feel like a really experienced independent researcher I pretended to be in the proposal. Also, knowing the things I have learned during my new postdoc, if I were to write this proposal right know, I would write a very different one.

Now I have to choose whether to accept the fellowship and learn scientific maturity the hard way learning new science and managing new funding in a new country simultaneously, or to stay in the US and develop my knowledge of the new scientific area more calmly (and have time to publish something in a reasonable journal). I have some other more mundane concerns about moving from the US to Europe right now, but they are less crucial.

I was told before that when one applies for permanent positions, there is a rather hard rule that on never rejects it, if offered. In the sense that if one rejects it once, one has zero chance of getting another one in future. This funding I am talking about is not a permanent position but it is still a rather big thing, as I far as I understand.

So finally, I have two questions:

1. Is there some more or less firm "rule" about rejecting major fellwships/fundings, like with the permanent positions?
2. Overall, does the idea of rejecting a respected fellowship on the grounds of not being confident enough sound reasonable, or typically one is supposed to go ahead and ride the rare wave of opportunity?

Answer 1

There is a difference between good funding and prestigious funding. The Marie Curie fellowships are prestigious funding, but not really good funding. They pay a lot in salary (in some fields it could be twice what you are making in the US) but don't offer much else. The duration of fellowships are no more than 24 months, I believe. There is no funding to hire a PhD student or even an RA or funding for the actual research. There is no guarantee of a job at the end. The Marie Curie fellowship is nothing like a permanent position. Again, it is very prestigious, so congratulations.

Apart from the salary (which I am guessing is higher), what does the fellowship give you that your current supervisor is not (e.g., how long is your current contract and can it be extended). This is really the type of thing you need to talk to your post doc supervisor about.