i've never used either but did own a FR-revolution which is a similar sequencer. that's why i linked to the manuals. all the info is in there. all the specs etc.
you should also use the search function here at gearslutz. there are at least a few threads on each of these machines.
you might want to look into a used yamaha RM1x. a lot of people love it for hardware sequencing.
so, the mobius is a monophonic sequencer. you can only sequence one note on one synth at a time. anything that accepts a note on message will lend it self to creating patterns with mobius but it isn't going to be something you make entire songs with though i'm sure there is some tedious multitracking way to do it.
the europa i know nothing about but it looks more robust and has more channels for sequencing multiple tracks at once. i suggest you check out the manual and youtube videos. there are some demos of it like this one: