I'm not from Germany, but I have ordered from both of those sites. Postage shouldn't be too expensive if you order enough items. It's not a flat fee, but it barely goes up if you add more items. One thing I did notice is that Amazon.fr sometimes has free delivery and they also have Kiala, which is very handy if you're at work during the day.
I think packaging etc. depends mostly on:
Who is packing your stuff. Sometimes you get lucky and it's well packed, sometimes it's terrible. It's totally random for all Amazon websites I've ordered from (fr, de, co.uk, it, es). I've had a mix of good packaging and bad packaging on all sites.
Who is delivering your package. If your mailman / courier sucks, your package will get squashed no matter how well it's packaged. Better to have a good courier and bad packaging. If you can see who is delivering your package (e.g. Deutsche Post) and you know they are good, you can be pretty confident you'll receive the package in good order.
In any case, if there's something wrong with your order (damaged, didn't receive, ...), you can return it without issues. So I suggest you just try it out and if you're not happy: return your sets.