I have had a bit of experience with this beast of a plant and while I am new, none of the downsides were listed. I bought a large piece of property in May and immediately had issues. The previous owner had a thing for spiny plats so I have quite a few of these scattered around the property, on very large one was located right above the access to the septic system. When I say large, the base as as big around as a 55 gallon drum and about 3/4ths as high and the swords on it approached 7 feet high and averaged 4 to 5 feet in length. Well I had to move it or pay a couple hundred bucks for the septic guys to do it. At the time not knowing anything about this plant, I assumed it was some form of cactus and went at it with a bush axe and regular axe. The bayonets at the end of each sword leaf were around 4 to 5 inches each. The hook spines along the sides were about an inch each and sharp enough to penetrate heavy leather work gloves. That aside a started hacking. and splattering the sap a bit on my exposed arms. I didnt think much of it and a half hour later my arms and neck were burning. I took a break washed my arms in cool water and went back to work and same thing happened. Note at the time I didnt have internet hooked up to even look it up. So I defoliated it and still had the drum sized base to work with and I chopped a bit under the soil level, brought my jeep around and hooked up a chain and after about an hour of chop/pulling got the 200+pound base out of the ground and rolled it into nearby woods where it still sits and is still green. The next day I notice my arms and neck are very splotchy. The next morning I wake up and my arms are itching...bad. Real bad. So bad it was ridiculous. And over the course of the next two weeks I go through a bottle of itch cream a day easily and have to take a couple benedryl every night to get to sleep. I am alergic to poison ivy and have had some nasty cases of it. PI pales in comparrison to agave sap. I have never itched so bad in my life and I grew up playing in the woods and outdoors. Then I look this creature up and discover the sap causes contact dermatitus and there is no cure aside from waiting it out which usually takes a couple weeks(which it did) and there could be a relapse in the same location at any time over the next year. I talked to my nursery guy about this thing, he told me he refuses to sell them due to the spine issue alone, he didnt even know about the sap and I have met other nursery people locally who told me the same. I still have a few of these including a moderate sized one still on the property and I havent yet gotten rid of them. I would recommend them to no one and if you have them, I recommend either gasoline and matches or C4 to get rid of them.