[Milhouse]

But one more question then, regardings both systems - I noticed, that RaspBMC in its current version seems noticably faster with the same cpu/gpu/core/ram OC settings and the same skin, etc. How could that be?

Pass... it would be useful if you could quantify that somehow, such as "Raspbmc is 2 seconds faster than OE when doing XYZ" (where XYZ might be opening a library of 200 movies). Presumably this is testing with the same addons, library, filesystems and network mounting settings (NFS rsize/wsize etc.). Maybe monitoring CPU behaviour during various activities would be useful to ensure the CPU frequency is scaling correctly (bcmstat.sh will confirm this).