Well if you're asking if it is easy to play:
Yes it is easy, but as with anything, it is hard to master. You shouldn't have any trouble with getting a sound out of it with your experience with clarinet. Bass Clarinet is an octave lower than clarinet and it has the same fingering, although there is an extra note at the bottom (d#).
But if you're asking if it's hard:
The easiest is alto saxophone. Bass clarinet is not that hard and is a very fun instrument to play, its range is incredible. Tenor sax takes a lot of air.