Personally there are lots of reasons that I went rb30 instead of stroker rb26. here are some
cheaper bottom end
ok, much cheaper bottom end. $000s.
more capacity (yes, there is no substitute for cubes)
more torque at the same revs. and less revs required for longer, happier life.
better rod/stroke ratio (rb26 is already terrible, stroked rb26 are worse again)
down sides for the rb30:
stuffing around with the impact of the taller block - gearbox bolts, radiator hoses, dump pipes, intake.