The tl;dr version of bees:
The ultimate benefit of investing in Forestry's Bees is you will be able to generate an "infinite" quantity of a wide variety of base resources.
There are a set of Bees that can be found, in hives, in the world, that can be combined, by breeding, to produce new bee species, and it is the species that defines what materials the bee produces.
With that in mind, and considering the fact that you are playing direwolf20, you need to answer this:
1. If you want an easy route to the production of infinite glowstone, quartz (nether and certus) and other annoying to get materials, then the Gendustry machines are what you want to look at. This will require you producing loads of RF, but you will use a machine called the Mutatron to combine specific species to get the species you need, and then splice in the specific productivity, lifespan etc traits you most desire.
2. If you want to spend what will feel like literally years of your life, painstakingly combining bees, over and over and over then base forestry is the way to go. Here you will have to combine bee species painstakingly with a chance to get an interesting mutation, and then desperately breed several more generations, by crossbreeding it with other species you have on hand with strong traits. Of course you don't get to pick which of the 14 alelles you get to keep in each generation so this is going to be tedious frustrating work. You will feel proud of any result you do get, but everyone else will be playing MC 1.10 or something by the time you are done so, basically, never do this option.
