I visit the DBG frequently, and I had a student who studied their volunteer training programs; I'm a very minor donor. I love the Garden; its variety of weird desert plants is impressive, and it has good educational exhibits and programs--birdwalks, talks about desert plants, etc. It also has night-time hikes where one can see night-flowering plants and bats [if one is lucky]. I have seen a Road Runner standing and trotting within about 15 feet of me, Great Horned Owls flying about 20 feet overhead, and lots of other animals I've seen nowhere else outside of zoo cages. The DBG is very well maintained, and attracts traveling exhibits of art and sculpture.
My student found that the DBG has remarkable training programs for its knowledgeable, dedicated volunteers. It is worth donating to, and visiting.