In what sense? If you mean packaging, they are both pretty excellent with regards to packing. On par with IST and Cheap-comics. Can't really fault them.
If you mean shipping outside of Poland, check the below:
Multiversum:
https://multiversum.pl/_cms/view/105...-shipping.html
Atom comics:
Send them an email or call to establish shipping costs
SKLEP@ATOMCOMICS.PL
+48 795 441 424
I would say that atomcomics.pl have the edge with regards to receiving comics from them in near mint condition and they have great customer service. I have received a comic or two from Multiversum with some very slight damage but they cover themselves claiming that their comics are not in ideal condition. However, at present they have the best preorder price and the majority of my preorders have been from them even though they are not as flexible in dealing with problems.