Only the base model Grand Vitara isn't 4WD, the other models have a full time 4WD system and to be honest the Grand Vitara is a surprisingly good off-roader.
I used to own an earlier one and it would go anywhere my D22 4WD dual cab would go (comparing stock to stock) provided you kept in mind the fairly soft shocks and moderated your speed.
They do benefit from a decent set of shock absorbers (like most 4 wheel drives).
The main downside is that they haven't got much space behind the 2nd row of seats but if you're using them for 1 or 2 people the rear seats lay down giving plenty of carry space.
Can't comment on the Jimny, never driven one but as compact 4x4 vehicles go I'm a fan of the Grand Vitara.