they are only more expensive because they include stands and grille. Otherwise they are identical to these
http://dynaudioprofessional.com/bm-series/monitors/bm5a-compact/ except have RCA unbal inputs
They haven't revised the BM5A-Compact yet to series II.
The regular BM5A are now in series II and should represent an improvement http://dynaudioprofessional.com/bm-series/monitors/bm5a-mkii/
Wow, $300 extra for stands and grills...hardcore.
When I was shopping for the BM5A's, I was attracted to the compact version, but no one local carried it. So I just ended up going with the non-compact version, which as you pointed out is a series II. I didn't even realize the compact wasn't a series II as well.