For function generators like Stages, my personal favorite is the Intellijel Quadrax + its expander. 4 envelopes with end of rise and fall triggers plus a CV matrix behind the scenes. IMO this packs more functionality that any of the others, including the mighty Maths. I also use a Befaco Rampage, which is also great and so easy to use but Quadrax is the workhorse. Only problem is there are zero around for sale though I read on one of the German retail sites that new ones are expected in July... I want two!