I use both BT and Spinosad - but BT goes directly on things I'm going to eat (broccoli, cabbage, kale, etc) and Spinosad goes on the leaves of things whose fruit I am then going to eat later (mainly my citrus trees, sometimes tomatoes/peppers depending on my infestation levels). The BT I use is for caterpillars, so I only use it on things that are destroyed by caterpillars. Spinosad will affect more than just caterpillars, so I use that mainly on things where I need multiple types of bugs killed - leaf miners, thrips, mites, etc. So they can overlap, but one is more specialized than the other.

Neem...I haven't found to live up to the hype. I've found it useful for aphids, but then again soap and water is useful for aphids and much cheaper. YMMV.

I think it's important to take time to identify the specific pests that are attacking your plants and then research the best way to treat them. For example, Bt is very specific to certain kinds of caterpillars. There's one kind that will kill cabbage moth caterpillars and tomato worms, two pests I have every year. There's another kind of Bt that kills mosquito larva and fungus gnat larva, but it doesn't work on cabbage moths or tomato worms. Spinosad is a broad spectrum pesticide that kills lots of different kinds of beetles and bugs that chew on plants, but it's not very effective on spider mites and it's overkill to use it on cabbage moth larva, and it can hurt bees if you use it on flowers when they are around. Probably the best way to get rid of aphids is a hard spray of water, and not any poisons. Another thing to keep in mind is that over use of any pesticide, even OMRI approved ones, can kill the beneficial insects who are your best defense against many pests.

Agree with Ohio - specific pesticide for the specific pest. There is no all-in-one pesticide that doesn't do more harm than good if for no other reason than that there are 10x the number of beneficial insects vs. damaging insects. And pesticides, just because they are organic, doesn't mean they can't do harm. Especially the "homemade concoctions". As for Spinosad vs. BT - totally different things so it isn't an either or.

Fungicides, if used per the label directions, are far less harmful and do tend to overlap some in effectiveness. But commercial fungicides vs. homemade things? No comparison in effectiveness.

Dave

spinosad only kills insects that feed on plants, aside from direct spray. Of course direct spray with soap, neam, and horticultural oil kills any insect also.