I received a post-doc offer in physics from a German University. The position has a fixed three-year term, which might be extended up to three more years. The original position description says that this is the A13 Z position, Akademischer Rat auf Zeit. It corresponds to a Beamter, or civil servant position. Since I am a foreigner, the inviting professor is asking, whether it would be OK for me to switch it to E13 instead (researcher), since my profile for the position in this case is not needed to be checked by the federal government and the documents would be prepared much faster and easier for the inviting University. The salary would then be increased, to match those of A13 (let's assume the same net amount).
What are disadvantages and benefits of E13 compared A13 if one ignores the difference in the salary scale?
Which one is considered better in a long term?
Some more information on the personal situation:
Let's assume I'd like to stay in Germany afterwards.
I'm going to marry before starting the position. My partner has two children from the previous marriage.
I am not a citizen of the EU or the Schengen group.