The main social benefit you're probably going to miss outside the EU is subsidised healthcare. You can probably get help from your company with health insurance. Likewise they probably should be able to advise on tax issues (chances are that taxes will be lower than in Germany). I had the good fortune to be offered a rather shorter overseas stint (~3 months) with my company and they paid all these costs for me; with a permanent relocation they may or may not be inclined to cover the costs but certainly ought to be able to offer advice if they already have a presence in your destination country.
The other, possibly bigger question is who you're going to socialise with. This can actually be easier in a foreign country than moving to another part of Germany - other people are more likely to find the new German guy interesting and more likely to want to help. It is worth finding out if the locals outside your company are generally regarded as foreigner-friendly and reasonably competent in English or German. If not, are there plenty of expats to keep you company? Are there significant cultural differences (especially noting the number of fairly conservative Muslim countries ~2000km from Germany), and would they matter to you?
Thanks a lot for the answer. I already looked a bit into healthcare and taxes. The former should by now be covered (was a bit of a hassle exactly _because_ even my employer didn't know if they need to take care of my healthcare, plus I'm getting married in the next weeks and need to take care of my SO then). The latter are lower, but actually not that much (much to my dismay..).
Socializing: Both my future wife and I plan to learn the language (if possible..). The culture is mostly friendly, depending on the place you're at in that country. And it's about as far away from a conservative Muslim country as possible. ;-) Now how's that for a spoiler?
I think what I'm worried about most are the small everyday things. Working all day and still socializing (not only with your coworkers, please). Finding a sweet spot to chill on weekends, if you cannot read signs and don't speak the language..
The other, possibly bigger question is who you're going to socialise with. This can actually be easier in a foreign country than moving to another part of Germany - other people are more likely to find the new German guy interesting and more likely to want to help. It is worth finding out if the locals outside your company are generally regarded as foreigner-friendly and reasonably competent in English or German. If not, are there plenty of expats to keep you company? Are there significant cultural differences (especially noting the number of fairly conservative Muslim countries ~2000km from Germany), and would they matter to you?